bdschobel of course hits the nail on the head. This certainly is the metric used when determining admissability of recorded evidence in a criminal court (for example, the police may record you without your permission or knowledge and use it against you when you're in a public place, but need a warrant to do so when you have a reasonable expectation of privacy, such as in your own home or a public restoom).

My guess is that there indeed were cameras found in other rooms. The fact that the hotel conducted a search of other rooms but refuses to discuss the findings seems suspicious. More telling, the fact that the camera allegedly had a label on it that indicated the room number is very interesting: if you planted a camera in a single room, why would you go to the trouble to label the camera with the room number?

Regarding the plaintiff's contentions about what this has done to their travel habits, this is perhaps a textbook example of the old phrase: "Just because you're paranoid doesn't mean they aren't really out to get you."