Having a gun truly is the best defense you can get for yourself, even if you're a master of mixed martial arts. If only because it's a lot quicker and a lot easier to shoot somebody that it is to disable them by breaking their limbs or knocking them out. It's one thing to just aim at someone and shoot, but if you're up close and personal and you see someone in severe pain(or pretending to be in severe pain), it's really hard for most people to be merciless. Even if they know that no thug would show them mercy if the positions were reversed, most people lack the "emotional shield" to go through with it. Plus, you can learn how to shoot a handgun decently in less than 10 hours, and it would take you quite a bit longer to become a decent fighter.
Considering that petty criminals are generally a cowardly bunch and would rarely attack one-on-one, you are unlikely to be at favorable odds. At best you'll be fighting two assailants, which is sadly where any kind of grappling fails. It usually very effective in one-on-one combat, but that's pretty much it. Grappling with someone who has a knife is a really, really bad idea. Stand-up striking arts are the way to go if you expect to be attacked by multiple opponents. I've found that it takes one very good punch or one good kick to make someone reconsider their position.
About the whole loony thing, most of them are not a danger to anyone but themselves, especially old folk. I've met several, especially in parks. As long as they don't appear to be dangerous and you're not a naive type of person, you have nothing to fear. Trust only people you know and stay vigilant, and I doubt you'll get in trouble. If you find yourself attacked by more than one person, fight with the intent to kill them all. Strike where it hurts, arm yourself with whatever happens to be in your surroundings and strike and/or shoot to kill.
P.S: Apologies if there is anything really stupid in this post, I was interrupted a grand total of 8 times while typing it >_>
Last edited by lordtiger; Dec 1, 2012 at 09:22 PM.