Originally Posted by neg58
But then you are released into the world again. Person A could check in with the correct documentation, and Person B could get on the bus and thus the cruise.
Once you give someone the KTTW card, they could hand it to another. Now, anyone with an ID can get into the terminal and the switch could happen there, but at least that is all monitored.
But giving someone else your KTTW would also require them to look like you as well. They check whether or not you match your picture in the computer when you board. It's the same as getting off in port and then reboarding.