Hotels that are reputable do not have any cameras in bathrooms especially in the United States.
In most places and especially in the United States it's illegal to have cameras in hotel or motel bathrooms and in hotel and motel rooms.
If a hotel or motel put cameras in their rooms or bathrooms then they can get sued and even shut down.
If you travel to a location outside the United States or stayed in a shady motel or hotel then it may be possible for a camera to be in the hotel bathroom or hotel room but also very unlikely.
If you do find a camera in a hotel bathroom or hotel room you could sue the hotel and even should bring the issue up with the hotel staff.
But like I mentioned it is very unlikely for cameras to be in hotel or motel rooms and bathrooms.
Hotels and motels do have cameras but only in public areas and hallways.