Are Cameras in Bathrooms Legal?
No. Generally, cameras outside are almost always fair game. That is the reason many buildings, particularly in very urban areas, have several security cameras at every corner of the building. This way, if anything happens on the property -- for example, a burglary, fire, or flood or an accident -- the building security can address it immediately. This also helps to apprehend criminals on the property.
Yes. For the most part, we do not have a right to privacy while in public places. Outside open air such as on the street, is generally considered a public place, so there is no issue about invading someone's privacy here under normal circumstances.
However, if a camera points somewhere which is not public (e.g., into someone's bedroom window) then there may be a privacy concern. Even when the camera is positioned outside, it cannot generally be oriented in a manner intended to invade an area where someone has a reasonable expectation of privacy. That is particularly true if the camera has enhanced capabilities that allow it to see through obstructions or in the dark. One can also not generally use a hand-held or portable camera outside to do things like look up women's skirts, peer through windows, or otherwise go from a public area into an area one would expect privacy.
No. A camera cannot be oriented in a manner intended to invade an area where someone has a reasonable expectation of privacy. One can also not use a hand-held or portable camera outside to do things like go from a public area into an area where one would expect privacy.
While bathrooms have almost universally been deemed a private place, dressing rooms, however, do not necessarily require full nudity. Thus, one could be on camera and not realize it every time they go clothes shopping. Fortunately, most national chains have refrained form placing cameras in dressing rooms out of concern for alienating their customers rather than issues over privacy laws.
Other areas like hotel rooms and locker rooms are considered private areas and security cameras are almost never used.
So, if you are in a place where you have a reasonable expectation of privacy like a bathroom, it would be illegal to place a camera there.