Given the MTA's budget woes, I'm not suggesting this thought experiment should be implemented. But I've had this thought in my head for a few years. Not sure why it's there and not sure why it won't go away, but maybe writing about it will purge it from my head. It has to do with the New York City subway system, a way to save people lots of money, if only they are willing to trust each other and be willing to absorb some costs when it comes to that.