Unlimited is a bit of a misnomer. If you exceed 5 GB, you come up on a special list. Rumor has it if you come up on the list three times for going over 5 GB (or if you come over once blasting past 5 GB such as
pyrobling did), they send you a letter saying you've been cut off from your data plan. Not sure what the rule is, but I would assume if you don't get the letter in time the $.02/KB rule would apply and you'd be stuck with a thousand dollar bill if you kept streaming.