I mean, when you give them a number on the phone, the guy at the other end is just going to be putting the number in the same place the website does.

When you pay in-store with a credit card, probably same thing.

EDIT: Well, unless, for the last case, one's using a cryptographic-signature-based mechanism, like the smartcard chip or wireless authentication. But if it's a magstrip or someone punching numbers in...