Are you suggesting that amtrak asks "are you really jewish" when you order a Kosher Meal? I'm not sure if that's even legal.
Or are you suggesting that Kosher, vegan, etc. meals only be made available to passengers for an extra fee?
I thought that what airlines often do is say that the special meals are for people who really need them, but dont actually verify it. They assume that most people will be honest, and it works out overall. I might be misunderstanding, but Im pretty sure thats who a lot of companies do it. I would also say that just because something is called a Kosher Meal doesnt mean you have to be Jewish to need it. If that meal doesnt have meat or some other ingredient that certain people cant eat, then that meal would make sense for them, even if they arent Kosher or Jewish. My point is, you can have a system that relies on most people being honest about if they really need a certain option, without having a full verification process of their religion or medical details.