From ada.gov
11. Q: Can I exclude an animal that doesn't really seem dangerous but is disruptive to my business?
A: There may be a few circumstances when a public accommodation is not required to accommodate a service animal--that is, when doing so would result in a fundamental alteration to the nature of the business. Generally, this is not likely to occur in restaurants, hotels, retail stores, theaters, concert halls, and sports facilities. But when it does, for example, when a dog barks during a movie, the animal can be excluded.
In TD a service animal would have a good chance of becoming disruptive and fundamentally changing the nature of the business.
I don't post this lightly as I live with a lady that is in a wheelchair due to spina bifida. I take accessability issues very seriously but even the best service animal could easily become spooked by the TD set.
You can't fix stupid but you can TPK it.
"Mamma always said that True Dungeon is like a box of Drow Poisons. Ya never know how you're gonna die."