The strangest part about all this is the way social engineering can yield a Live Account.
"Hello, yes, I seem to have forgotten where I live, could you tell me please?".
"Hi, yes, well this is quite embarrassing, but not only did i forget my own address, but somehow I seem to have forgotten my phone number too. Couldn't quickly look that up for me could you?"
So okay, the more likely scenario is this
"I just wanted to make sure my account isn't registered under my old address, could you verify that for me" and "I just wanted to make sure my old phone number isn't associated with my account - which one do you have on record?".
But the point is neither of those pieces of information should ever be given out full stop.
If i was a legitimate caller that forgot I registered my account while I was living at an old address, there's nothing to stop me remembering what that address was and trying again.
If you really are smoking so much pot that you can't remember where you lived 2 or 3 years ago, then perhaps you have bigger problems than not being able to log into an XBox Live account. Perhaps, given your propensity for short term memory loss, you would be someone who benefited from writing your username and password down.
Ooo nooo.. writing your username and password down. Now anyone that breaks into your house or pretends to be your friend could steal it. Again, I submit that if someone broke into your home, or you had "friends" habitually stealing from you, your problems are far greater than the loss of a gaming account.
BTW - although you do save a few quid signing up for 6 months or more using credit cards, given the number of online gaming accounts that are stolen from all gaming worlds, I would think it would be just a matter of self-preservation to use gaming cards instead.
I'm not casting blame or pointing fingers at victims, I'm just suggesting that now we know no one working for these corporations gives a shit about you, you would be better off protecting yourself however you can.