Those use cases are why you charge extra to extend the door lock timeout. Prostitution and drug use isn't a particular problem as long as you can economically

Those use cases are why you charge extra to extend the door lock timeout. Prostitution and drug use isn't a particular problem as long as you can economically clean up their mess. Receptacles for unflushable trash and sharps should make them less of a problem. Squatters that refuse to pay only become a problem when they cause denial-of-service to (potentially) paying customers. Back when bathroom attendants were economical, they were the ones that could chase out or discourage the undesirables. I didn't mention this, but one of the robotic bathrooms I have seen encourages people to leave in a timely fashion by filling itself with water as part of the self-cleaning cycle. That program mentioned the difficulty in getting the squatters out while still serving regular customers. [Edit for cousin post:] After the door lock times out, the GTFO timer starts. Don't be surprised if your stall fills with unpleasant odors (mercaptans) and sprays of cold water if you decide to try to squat in there without paying.