Legal question reguarding contracts with MSN

[Raizer2001]

I am wondering if this loophole in the MSN $400 free deal is legit..if you are under 18 and you sign up for this agreement at a bestbuy store..sinse they dont check ID half of the time..if you are under 18..and sign the contract..they cant legally hold you to it can they?I always understood it that if you were under 18 you couldnt enter into a legally binding contract...is this correct? So really you could get away with it with $400 free like back in the old days when cali residents could just cancel.