mmx,
I am not sure what derived your opinion, I am pretty much confident about it that he does not have to register as I am in the same boat and I have confirmed this with several attorneys. Unless all of them were wrong and you have read something very specific instructions.
If you last entered after sepxx, 2002, you do not need to register, that's the law so far. Please show me where it's written that the burden is on you to do it at the airport.
I do know the consequences of a mis-advise, I wouldn't advise any one without being aware of it, and in this case I myself is not going to register due to the same situation.
Thanks