I'll repeat: holding the police financial liable for not preventing crimes is like holdnig soldiers liable for not winning battles. It just doesn't work.
You misunderstand me: I don't think they are actually liable, and I don't think they should be liable. However, police often represent that they are, and a lot of people - an overwhelming majority, I'd wager - think that the police are. My initial comments about truth in advertising aren't because I think they should protect when they don't, but because they lead people to believe they do something they don't do, and shouldn't do. And this is aside from gun control advice, "buy-backs" and confiscations, that some police also do, when in fact gun ownership is the single best way to fight violent crime.