No, it has to be registered through the site, so they can transfer the points... Otherwise there's no way to trade points. Do you have enough points? It won't let you bid if you don't.
Attach a facebook or twitter account, confirm email, verify a credit card or phone number. Go to your profile and complete some of the things it asks you to do.
I hope no one would do that, but it does happen. I always send with tracking and I keep the receipts and giftcard numbers to prove they have money on them, and prove where it's spent if needed. Lots of safety ;) thanks for the heads up