Highlight - or lowlight - of my day in PHL was the guy that (a) refused to let guy with canes get in front of him when the agent decided to preload canes-guy (and I quote, "I'm zone 1"), then a few moments later when zone 1 was called, broke out of line and became zone zero, apparently deciding the 3 people in front of him could not possibly be zone 1 also (older couple, then me).
Grrrrr to this state of 'me first'.