I recently used the washroom at a Starbucks. The one where you have to enter a code to get in. Once I was inside, there were no knobs or any mechanical way to lock the door - just one circular button with a lock icon on it. I pressed it, and the button lit up as green. Pressed it again, it lit up as red. No indication on what light colour meant what. Does red mean it's unlocked? Or does it mean it is locked, since red usually indicates no entry.

It made for the quickest pee break ever.