Many many years ago I used to take the Southern Crescent back and forth to Georgia Tech from my home in Boston. My very first long distance train experience occurred only because that train allowed pets in bedrooms and it was the easiest way to go home with our two cats.
A lot of this fake service animal problem would be alleviated if Amtrak offered more services for regular pets, not to mention a good strong new market for Amtrak.
Nothing would change for service animals, but how about a couple of bedrooms for other pets maybe with rubber flooring and washable seat covers and a pet cleaning fee? Amtrak had a great opportunity to carry larger pets in climate-controlled baggage/dorms but not sure if that is a real possibility because I don't know if the baggage area has A/C and heating.
The Auto Train is a great platform to try something along these lines and the market is certainty there.
Traveling with pets is problematic. People love their pets and this could create a whole new market for Amtrak and stop this fake service animal situation.