That just points out the beauty of states that have concealed carry for their citizens. LEOs in Texas have to enter a situation like that thinking that it's very possible that the guy in plain clothes with the gun is the GOOD guy. They can't assume that only bad guys wear plain clothes and have a gun. I love the people who don't see a "need" for anyone to carry a gun. That they are "looking for trouble". For most victims of crime "trouble" finds them. At least by carrying a gun you can equalize most threats you'll encounter. And if your would be perp. is armed with a club or knife, you then are able to defense yourself from a position of strength. But most likely the bad guy will run and look elsewhere for a more suitable (read as unarmed) victim. I don't understand why one would WANT to put themselves at the mercy of a criminals conscience, unless they live somewhere they'd have to. diclaimer:Carrying at a theme park is not a good idea.
Actually, carrying a gun may only bring trouble in many situations. Criminals do not attack people on high traffic streets, giving them warning half block away and time to throw your gun. They attack in dark corners, empty train stations and so on. They attack when they are already too close with a gun or khife already out. Try to get gun out and they will attack, simply reaction, not a need to kill. Most criminals wants your bag, your jewerly, money, giving it to them, definitely unfair but better then playing hero and loosing your life(Ghost). So no, having gun does not really protect you, unless you carry it in your hand ready to fire every moment. Guns give a false feeling of safety. That was regarding civilians carrying guns.
As for LEO, I agree that some has to do it due to nature of their jobs or policies. Other then that leave it home. Less guns on streets better for everyone. People die in crossfire and it does not matter if it was bad or good guys gun.
As for bad guys, no ammount of LEOs may solve the problem. It takes much more investigation, undercover, planned operations to find roots and send bosses and those who sell illigal guns, dugs, and so on to jail, breaking gangs apart and leaving them without support. LEOs can treat the symptom by randomly catching bad guy here or there but the problem will remain.
One more thing to consider, if LEO lives is criminal area, he can do much good, if he lives in quiet area, he can never see any crimes and having his gun with him off duty is simply pointless.