As for the alcohol thing - sounds like an ignorant waiter since it's not illegal for parents to give their children alcohol in their presence (at least not nationally). There are a lot of local laws (weird dry towns and such) so it might have been something like that.
Yes. For people who use real computers, middle button = "paste selected text".
Clicking the scroll wheel will do that as well. But I guess you know that since you're a "real computer" user.
Still, it should not be doing it.
It uses the functional programming style available in python which allows single liners that can do a lot (though ideally you will split them up a bit for readability).