Maybe maybe one day soon, every coupon, voucher, certificate, chit, card, and or every other redeemable item that AS generates will have unique ticket or other identifying number so that all of this nonsense, whether it be a guest upgrade cert, or a $ off cert, or a companion cert, or anything else in the above list not require the need to see an agent. This would obviate the need to see anyone for check-in, whether or not the "Cert" is redeemed, because if you tried to upgrade someone again using the used cert, the "You have been banished to row 45" gods will come out and make quick business of you.

[For those of you unfamiliar with row 45 of any of the AS fleet, its a cold and not so comfortable ride]