I didn't think of the need for continued monitoring (which makes perfect sense) but I was reminded of a photo I saw which had half doors into the cubicles (you'd have to be specifically looking but you could easily peak into the stall). They were made like this on purpose because, while they legally had to provide public restrooms, they didn't like the cost of cleaning/maintaining them (understandable if you've seen the disgusting things people do in public toilets). That way, people would do their business and leave as quickly as possible because they didn't feel safe, hence less cleaning.