I don’t find this claim persuasive in the least. I could just as easily assert without evidence that fees reduce cleanliness because patrons feel they’ve prepaid for their messes to be cleaned up, and security because resources that could be applied to safety and reducing crimes against patrons are used to enforce fare collection and secure methods of payment instead.

> But it's a persuasive argument.

Persuasive to what type of people?

At that point just make separate no fee, low fee, and high fee train cars with varying levels of poor people and/or cleanliness.