I recently applied for the TSA's Global Entry program, which for a small fee will allow me to keep my shoes on when I go through airport security. At the end of a short interview with a very pleasant and professional TSA agent at the airport, he told me that I would receive an e-mail in a few minutes with the approval, and in fact I received an approval eight minutes later.
The approval included this sentence, not as puzzling as Google's licensing agreement, but one that caused me to think for a while:
If you enrolled in Global Entry, you may begin using the kiosk immediately. Global Entry cards are only issued to Global Entry members who are U.S. citizens, Lawful Permanent Residents or Mexican Nationals (who are not current SENTRI members). Global Entry cards are not valid at the Global Entry kiosks.
I was gratified to learn that I can begin using the kiosk immediately, but bemused to read that Global Entry cards are not valid at the Global Entry kiosks. Where, then, would they be valid, if not with the agency that issues them? I've thought about trying to use mine to ride the streetcar.