[rdl6989]

A simple “in use” sign that comes up when the lock is turned would be better.

[Red Badger]

You know the Japanese! They have to apply electronics to everything!..............

[Boogieman]

But that wouldn’t satisfy Japan’s fetish for novelty.

[ProtectOurFreedom]

I'd patent that idea quick, if I were you! It's brilliant.

You could even start up a portable toilet company and find a good spokesmodel to pitch the toilets. Maybe even your wife. Oh, wait, that's been done!