On a very full Metro ride into work this morning, the driver chided us riders in the typical fashion as he drove to the next stop.

Attention customers, when you hear the chimes the doors are closing, please do not block the doors, if you block the doors this train with be unloaded.

Every time I hear this threat, I recognize its futility. We, already on the train, are not blocking the doors, and have no motivation to do so. We, like he, wanted to see those doors close and move on with our trip.

The right audience is the people on the platform waiting to board, they are the ones who would be blocking the doors; however, addressing for them this is the wrong incentive. They selfishly are not concerned if the train de-boards. If they do not push their way onto the full train, then they are forced to wait for the next train. If the push on and cause the driver to unload, they, again, are forced to wait for the next train. But if they are able to squeeze on, and the doors still close, they get to ride this train, and get where they are going sooner.

In over a year of Metro riding, I have heard this threatening tactic again and again. Only once did I hear a driver give an incentive that actually made sense. Once, while at the station, a driver announced to those on the platform.

Attention passengers boarding this train, this train is full. There is another train directly behind this one. The sooner you let these doors close, the sooner that train can arrive to pick you up.

Surely enough, the people did not try to cram on, the doors closed and the train moved on without incident. Right audience, right incentive.