Filter Multicast

Question

Modem: WRT310N Firmware: 1.0.9.0 Build 4 (Latest)
192.168.1.1 > Security > Firewall > Filter Multicast
If I want to allow Multicast traffic on my network, does this box need a "Check Mark" or does it need to be "Unchecked"
Thank you for your help!
Here is the manual's pdf text:
Filter Multicast Multicasting allows for multiple
transmissions to specific recipients at the same time. If
multicasting is permitted, then the Router will allow IP
multicast packets to be forwarded to the appropriate
computers. Select this feature to filter multicasting. This
feature is not selected by default.
Here is my router's internal help text:
Filter Multicast. Multicasting allows for multiple transmissions to specific recipients at the same time. If multicasting is permitted, then the Router will allow IP multicast packets to be forwarded to the appropriate computers. Select Enabled to filter multicasting, or Disabled to disable this feature.
WRT610N Manual:
Filter Multicast Multicasting allows for multiple
transmissions to specific recipients at the same time. If
multicasting is permitted, then the Router will allow IP
multicast packets to be forwarded to the appropriate
computers. It is selected by default. Deselect this feature
to disable it.
WRT54G2 Manual:
Filter Multicast Multicasting allows for multiple
transmissions to specific recipients at the same time. If
multicasting is permitted, then the Router will allow IP
multicast packets to be forwarded to the appropriate
computers. This feature is selected by default. Deselect
this feature to disable it.

Answer 1

So i re-read some of these articles. And this is the most professional article, the most trustworthy in my opinion as it was taken straight from a textbook written by a Cisco author. However what ails me is that it is from 2006 and for a different linksys router.
Filter Multicast (Disabled)— This setting allows multicast traffic to be forwarded to the appropriate destination. Multicast traffic is traffic destined to multiple hosts. This allows the traffic to be sent one time, while allowing multiple registered hosts to receive it, which it more efficient than sending the traffic individually to each host (which is a process known as unicast). A host registers to receive this multicast traffic by virtue of the fact that it is running an application that is configured to listen on the corresponding multicast IP address. Multicast is frequently used for the transmission of multimedia and streaming data. Multicast traffic is frequently filtered when it is either unnecessary (for example, because no applications that utilize multicast are running on the network) or to prevent multicast-based attacks from being initiated (for example, to prevent an attack that uses multicast traffic to saturate a network with bogus traffic, thus effecting a DoS on the network). Although somewhat counterintuitive, you want to disable filtering if you want to permit multicast traffic.
If you read the last few lines carefully,  
1) Multicast traffic is frequently filtered when it is either unnecessary (Filter = block)
2) you want to disable filtering if you want to permit multicast traffic (Disable = Uncheck)
So this confirms that the manual is actually correct. If you want to "Enable" I.E. "Allow" Multicast Traffic. You must "Disable" the "Filter"
Basically uncheck the filter to allow
Check the filter to block (just like everything else on that page)
http://www.ciscopress.com/articles/article.asp?p=598649&seqNum=5
So if this does in fact not work, and the opposite is true. Than it is simply a bug/glitch in the firmware and it should be reported to Cisco/Linksys. However, how do we do this? Everytime I contact them, they just want to know my S/N of my router before they talk to me, and since its too old they say sorry cant help you.
*Edit* Here's another confirmation link from cisco on Multicast Technology:
http://www.cisco.com/en/US/docs/internetworking/technology/handbook/IP-Multi.html
Routers are typically configured with filters to prevent multicast traffic in this address range from flowing outside an autonomous system (AS) or any user-defined domain (Again, in this statement Filter = Block)
"Filter Multicast" Enabled (Checked) = Enable the Filtering (Blocking) of Multicast Traffic
"Filter Multicast" Disabled (Unchecked) = Disable the Filtering (Blocking) of Multicast Traffic
Which makes sense. For every other filter on that page, if you "Uncheck" them, such as "Filter Anonymous Internnet Requests" then it "Allows" your network to be pinged. But if you "Check" that box, it prevents your network from being pinged.
Does anyone agree/disagree?