I am not aware of any other commodity that one assumes has been obtained because payment was either taken, or seemingly taken, and a reciept or email was issued. I am sure a lot of us use internet for other transactions - until we have the goods in hand we dont assume the transaction is complete. Everyone who buys airline tickets knows these are rarely issued instantaneously and that the ticket is issued sometime after the financial transaction is made and this is confirmed by a subsequent email (or the initial email but delayed).

Even when the payment is truly taken, one has still to confirm (by recipet of an e-ticket) that the deal has been completed. Changing award tickets is another situation this may happen as it is possible for waitlists to clear etc and see reservations on line but until you get a new e-ticket no change has happened.