I’m guessing this would run afoul of anti-springtrap laws in the US.

If the custodian of the restroom starting spraying undesirables with water, there’d be a lawsuit or maybe even assault charges.

I’m not a lawyer, but automating that should be even more illegal:

First, it implies premeditation. Also, it could endanger people in corner cases. What if someone is forced out with their pants down, wheelchair users, etc?