I'd like to think that if I was given a brand new laptop as a replacement for a much older model (which they could have continued to repair, but choose to do the right thing), I wouldn't try and get something (10.5, $129) for almost nothing ($9.95) by trying to fake the 'purchase' date.
I'd like to think I'd be happy that I had brand new hardware running a great OS, and if I wanted to update, I'd just pay the price, like everyone else.
Or, if you prefer - if they had fixed your iBook, and it was running perfectly, do you still think you'd be entitled to a 9.95 upgrade to 10.5?
*shrugs shoulders*
I can understand wanting it, but you are outside of the purchase date that Apple set as the limit, and you didn't have to pay for the macbook to begin with...