I am already paying for data so why is there a charge for tethering?

Question

I would really like to upgrade my Droid to a Droid 4 and use the WiFi hot spot feature. I have not done so yet because Verizon wants to charge me to use this feature of the phone. This appears to be illegal and I cannot understand and justify paying a monthly fee for something I am already paying for. I have seen a few posts on other websites trying to explain why Verizon or any other provider can charge for enabling a feature and not providing any additional service to the consumer however they are all very flawed attempts. I just want a VERY VERY VERY good reason why this is legal and justifiable. Please give me a convincing argument as to why anyone can charge twice for the same thing.
Tethering does not increase the data capacity of the phone. Tethering allows the phone to act as a bridge (modem) between a device to the network.
Q: Does Bandwidth increase?
A: No, if the bandwidth to your phone is 8 Mbps, enabling tethering does not change the bandwidth therefore if a YouTube video is running on the phone and three other devices tethered to the phone they will be sharing the 8 Mbps bandwidth. This means that each device would only be able to use 2 Mbps of bandwidth under heavy usage. (You will not actually get an even split for several reasons and all combined will be less than 8 Mbps but that is due to overhead and OS limitations.)
Q: Am I allowed to use more data now that I am paying more?
A: No, if your data plan is for 2 GB per month, you will be charged extra for using more than 2 GB in one month. This includes the data usage of the phone and other devices while they are tethered to your phone.
Q: Is there any reason to charge for tethering?
A: (My opinion but I would like to be proven wrong.) The only possible justifiable reason may be for those who have unlimited data plans. Verizon and other providers must provide a level of service that customers will be pleased with. I could be wrong but it would be difficult for someone to use too much data on their phone alone. (I know there are exceptional cases but this is true for the majority.) Verizon and other providers plan the network based on an average (i.e. 1 GB per month) usage for each phone with data. It is much easier and more likely users would consume more data if a device such as a laptop is tethered to the phone therefore users with unlimited plans would cost the provider more money to increase the bandwidth of the backbone. (Limited plans will be charged more but unlimited data customers are not as there is no limit, which is a problem.)
IMHO: The right thing for Verizon and other providers to do is to stop requesting that phones be shipped which require a provision from the provider so they can charge for the feature. There is legal precedent that it is illegal for a provider of a service to charge a customer for additional devices using their services if the provider is not providing additional service.
In order for Verizon and other providers to address issues with network capacity and unlimited data subscribers there are a few options available. One is to provide an incentive for those users to switch from unlimited to limited data plans or provide a credit for a device upgrade, etc. An other option is to keep things as they are with phone provisioning but provide tethering to limited data users for no additional charge and to charge users with unlimited plans for tethering. (BTW: I think is the best option.)
FYI: I do have an unlimited data plan and would be willing to switch to limited data if tethering were included and the prices were the same. Right now there is no incentive for me to switch to a different data plan especially if I need to pay for tethering in addition to limited data. I currently have an iPad with AT&T service which is an additional fee I am paying but if I drop the AT&T plan, upgrade my phone, and add tethering, I would be paying more and getting less so why should I? (The less is that my iPad would not get email updates, etc. except when I turn the WiFi hot spot on, which I understand runs down the battery so you do not want it on 24x7. Oh, another reason Verizon and others should not charge for tethering as tethering is not available 24x7)
Please I would like some straight honest answers to why it is legal for Verizon and others to charge for tethering and why I should pay for it.

Answer 1

I want clarify what I am asking for as I fear that many people may be thinking what Wildman stated which is not true. I think it is presumptuous for Wildman to think that I am not sincere and that I will not award points for a correct answer. The closest one to come to a correct answer thus far is jimfitzgerald however I need to see the policy or something in writing that explains what jimfitzgerald stated.
To help clarify what I am looking for, I will respond to some earlier posts as I think it may help.
BTW: I think it is premature to ask that points be awarded but I will put a deadline and a default to this discussion. If I don't see a good answer to this post by next weekend, I plan to award the points to Wildman as the points seem to be of importance. I am actually hoping that a good answer is provided so that it will help anyone else who is in the same situation as myself. I think there must be a good answer as I would hope that carriers would not charge for this feature if they are really not providing an additional service. I also would hope that customers are not gullible enough to pay for something twice which on the surface this appears to be. This does seem to come up enough that the carriers should do a better job explaining what they are providing.
From: jimfitzgerald on Feb 18, 2012 at 12:06 PM
Quote: "Also, the tethering plan does add capacity to your plan."
Response: Please provide a reference to the Verizon Source which states this and I will award points as this is an acceptable answer and is what I am looking for as stated in my original post. I cannot just accept a general statement like this as it will carry no wait if I get charged for going over my data limit.
From: rcschnoor on Feb 18, 2012 at 1:21 PM
Quote: "Question #1 ... you will be consuming TWICE as much data ..."
Response: This is incorrect as the 4G LTE connection will not be able to provide any more data per second than the phone itself. I think you meant to state that you may consume your limit of n GB per month in a period of a week on a laptop verses 3 weeks on the phone which is correct. If you continue to consume data past your limit, you will need to pay more for it so what is your point? If you don't pay more for going over if you have the tethering plan then that makes all the difference. This would be my misunderstanding and would be an acceptable answer. If this is the case, please point me to the Verizon documentation which states this and I will award points.
From: rcschnoor on Feb 18, 2012 at 1:21 PM
Quote: "Question #2 ... You get an ADDITIONAL allowance for your use when you activate a mobile hot-spot."
Response: This seems to allude to the fact that I may not understand how data usage is counted when tethering is added to your plan. Please provide a reference so I can read it and I will award points. Hopefully we are coming to answer here.
From: rcschnoor on Feb 18, 2012 at 1:21 PM
Quote:  "Question #3 ... but I don't think anyone would be happy with a monthly data bill of $60+ dollars."
Response: You are correct which is why I am having an issue with this. If I upgrade and keep my current unlimited plan, I will be paying $75 per month for data and tethering. To make matters worse, currently I am not a heavy data user as much of the time I have access to WiFi. I am considering switching to a 2 GB per month plan based on my current usage but I hate to give up my current plan as I will not be able to go back. I will switch however if the tethering was not an added cost or there is in fact an additional data allocation for tethered devices. I already feel that I am overpaying for data based on my current usage. The problem with switching plans is I could see if I have tethering, I may go over one or two months per year as once in a great while I need access and do not have WiFi available.
FYI: Here is a breakdown of my current usage.
          - Verizon Phone: (Unlimited data @ $45/month) Average Usage 0.23 GB/month
          - AT&T iPad: (2 GB/month @ $25) Average usage 0.89 GB/month
I do have another problem with switching which is unrelated to the data plan but is related to usage but will increase my cost per month.
From: jimfitzgerald on Feb 18, 2012 at 1:33 PM
Quote: "Or, in summary, charging for tethering is a way to make the people who use lots of data pay for it, rather than having everyone share the cost whether they use it or not."
Response: Sorry but my experience is just the opposite.
I would like to thank everyone who has tried to answer this question. It looks like there may be an answer but I would like to see it explained in black and white from the Verizon site. I cannot switch plans based on posts in this forum alone. If I were to switch then get hit with additional charges one month, I cannot call customer service and say that jimfitzgerald and rcschnoor told me that there was an additional data being provided to tethered devices.
I hope this helps and I hope this can be answered soon.