The kind of person who would do that once would probably be the kind of person who would do that many times, thinking it's a clever way to bypass the system. Ho

The kind of person who would do that once would probably be the kind of person who would do that many times, thinking it's a clever way to bypass the system. However, being the operation who marks every toilet they see as red 100% of the time is just as if not more suspicious as the person who other people mark red after the fact 100% of the time. If we really want to take it up a notch, we have ways to do so. Deviancy, countermeasure, arms race all over again - but few such arms races are actually worth the hassle.