ITunes 90 day lock out on iMac - only one AppleID can use a Mac at any one time?

Question

Just found out, the hard way, about Apple's patently ridiculous "90 Day Lockout" policy on iTunes (Match, Purchases download and pretty much ALL the useful features).
Apparently, at least according to Support - who feigned surprise that this was an issue - if you blow £1,200 on an iMac to be used by two people in your home and have paid Apple an extra £25 a head for iTunes Match, you're terribly gullible. And stupid. And a potential music thief.
The real problem is that Apple, probably in a bid to secure record label agreement to iTunes Match and in a vain attempt to curb unlawful music sharing, has decided that NO MORE THAN ONE APPLE ID can be associated with a machine ID at any one time, for iTunes purposes.
This is fine on iPhone, iPod Touch and even iPad. Those are hardware that only one person can use at a time - there is no "multi-user" capability.
Macs, though, are a different matter.  In Apple World we're all filthy rich and each member of a household is expected to own a separate Mac machine (iMac, MacBook Pro or Air) to be able to use the functionality and music they've paid for in iTunes and via Match.
If you're stupid or poor or just think a Mac per person in a household is consumerism gone mad, you are stuffed.
In our case we bought an iMac. Set up two separate and distinct User IDs and one of us set up iTunes and activated iTunes Match.
Next day the other went into their User account, set up iTunes and then activated iTunes Match. A very very vague message popped up alluding to "transferring an Apple ID to this machine" and referencing inability to use this AppleID on another machine for 90 days. That seemed OK. The AppleID had been associated on an old Compaq netbook for iTunes, so the assumption was that it was that association that was being transferred to the iMac.
WRONG!
What had happened was that the second person to sign in to the iMac and set up their TOTALLY SEPERATE AppleID on a TOTALLY SEPERATE iTunes Match library and account had effectively locked out the first user from their iTunes account.
So, if you're a family with individual iTunes accounts and iTunes Match don't bother with Apple Mac products. For the cash you spend on one mac product that only one of you will be able to use iTunes on EVERY 90 DAYS, you'd be better off buying separate, higher spec Windo$e laptops to sync with.
Apple has really really fouled up on this.
Support initially justified this lock out policy as being to prevent Johnny Fileshare from zipping round to his mate's house, logging into iTunes with his AppleID on his mates PC or Mac and downloading his paid for iTunes library onto his mates Mac as a gift.
Just how likely such a random outburst of philanthropy at the expense of record labels would be is beyond me.
During a near two hour call with support (use the Call Me function - at least the call is free) eventually, after an escalation, the tech agreed that the 90 days AppleID  lock was pointless as Apple themselves publish details in their knowledge base on how to circumvent music sharing restrictions and combine iTunes libraries - even helpfully including details of how to put said combined iTunes library on a memory stick. Johnny Fileshare can then nip round his mates house and share his iTunes content with his mate until the cows come home.
Even worse, Apple even allow you to burn to CD a combined iTunes library up to FIVE TIMES!
But, when it comes to logging into your own iTunes account on a shared Mac? Forget it matey. You'll steal music and can't be trusted.
Well FU too, Apple.
But wait! You may think you're OK because you weren't foolish enough to hand over £25 for iTunes Match...
BEWARE: THE 90 DAY LOCKOUT IS ACTIVATED THE SECOND A USER ON A MAC ACTIVATES EITHER:
1. Automatic downloads, or
2 iTunes Match
OR IF THEY HAVE THE TEMERITY TO:
1. Check previous purchases
THIS RENDERS ITUNES AS A PRODUCT/SERVICE WORSE THAN USELESS ON SHARED MACS.
We have 82 days to wait for one of us to regain access to the library that cost us a fortune to build in iTunes.
1 Week old iMac is being boxed up & returned to Apple Store.
Two high spec non Apple  laptops being bought as a replacement. The change to be spent on petrol or pasties - which ever the UK  is running out of most...

Answer 1

Yes, I am having this problem because I have 2 Apple IDs/iTunes accounts.  Mind you, I don't want 2 accounts but Apple forced me to make a new apple ID when they started requiring email addresses as user ID.  This was the first big mistake that Apple made.  Their second mistake was not allowing people to simply merge these accounts.  Had they not made these mistakes initially, many people would still only have one Apple account/ID. Some bloke ought to lose his job over that. 
However, I understand this isn't the same problem as having multiple household members using the same computer.  It seems that Apple could figure this all out by either authorizing multiple users at the time of purchase, or allowing a handful of users to download to one computer. After all, if I bought a hard copy of a music CD, I could certainly allow my son or daughter to listen to it or download it to their computer.  Next thing you know, I'll have to sign a release saying that I am the only person that uses my iPod.
I am also returning not just one but 2 brand new Mac computers ($4500 coming back from Apple to my wallet) because I am so fed up with the poor customer service response that Apple has given this problem.  Not only did they take a ton of my money for iTUnes songs, but then they restricted my access to those songs. I think it's criminal and I wouldn't be surprised if this issue ended up as a class action wrongdoing suit.  I have to admit I've considered talking to a lawyer about it myself.  I am so sick of large monopolizing companies thinking that they can treat their customers poorly and expect us to sit back and take it. The good news is that this is a free country and I can choose to throw my money at any old company I choose..........Toshiba here I come.