If there's a disaster, do you go over to your neighbor's house with: a) a covered dish or b) a shotgun? It's game theory. If you believe your neighbor is coming over with a shotgun, you'd be an idiot to pick a); if she believes the same thing about you, you can bet she's not going to choose a) either. The way to get to a) is to do a) even if you think your neighbor will pick b). Sometimes she'll point her gun at you and tell you to get off her land, but if she was only holding the gun because she thought you'd have one, then she'll put on the safety and you can have a potluck.