The answer is that we need to invent a culturally acceptable bathroom transition warning call.
Like, when you're approaching the door from inside you shout: "AND I'M OFF!" And from the outside you proclaim: "MAKE WAY!" In the event of overlap, the person inside moves out of the way for the person on the outside, who has to do a thing.
See, how easy is that? Now, start seeding society with cultural cues.
Commenting by HaloScan
