Cooper and Hudson sit on the edge of my tub while I'm showering. They'll also peek in and occasionally come INTO the shower being careful to stay in front of me where the water doesn't get them much.
I don't make my cats wear collars. To get outside they'd have to escape my apartment, go down the elevator or open the stairway door and go down that way, then they'd have to open the door downstairs... Don't see it happening. Besides, I just don't like collars on cats.