Of course they don't want hookers hanging out in their lobby but this is not what this post is about.
A guest bringing a hooker through the lobby to their room is not the same as hookers hanging out in their lobby.
If a guest at a 5 star hotel, paying the large 5 star room price, chooses to bring a guest to their room, the hotel is not going to be concerned about.
There is no way a branch of western international corporation like Hyatt is going to discriminate based on gender identification. Don't worry about it. If they do, just start to dial their international help line.
If anyone is wandering around Chiang Mai looking for spicy salad check it out. I doubt it will be there long as they go back to work in the cabarets soon.