Rules of Conduct

So a lot of game shops, especially the ones where they play a lot of Magic, have posted rules of behavior--generally stuff like

And there is often an expectation that Organized Play DM's are somehow responsible for enforcement

Which is a little crazy--I mean, for me, personally, I have very little interest in rules enforcement of any kind....I prefer shops with more playful signage

But I bet there is some good justification for some rules & I am curious what that may be. Maybe it is time to start a new tumblr to post Game Shop rules?