That's kind of the point of politeness rituals in the first place, isn't it? To see who can be bothered to spend some extra effort to fit in and who doesn't care enough about the tribe to make the effort.

So... human proof of work? Wonder if we could start a new politeness trend by asking our tribespeople to solve short hashes

After having close contact with someone who do not follow these protocols, I came to conclusion they are much more then that. If you consistently do not follow them, it ends up being impossible to include you. Even if others put conscious effort into including such person, the end result is exclusion and everybody spending huge amount of extra effort.

(Spittlespraying screaming, wildly pointing fingers...) DISCRIMINAYSHUN!1!!