I have no desire to "surprise" a person in a gun fight. I want to avoid all gun fights. Most criminals, like all predetors prefer to prey on the weak and helpless. Seeing an openly carried firearm will often cause them to move on to a weaker target. OC is a deterent to crime. It is quite possible that there will be no gunfight if the criminal knows you are armed and sees your weapon before hand.
Well said, gutshot II.
Many have responded here and elsewhere that a criminal is likely to attack the OC, the same way they attack cops. Actually, criminals almost never initiate contact with cops. They avoid them like the plague. Usually, the only criminals who attack cops are being tracked down, contacted, questioned, detained, or arrested by the cops. The exceptionally few that do initiate violent contact with cops usually have a "suicide by cop" mentality. To date, that hasn't happened with OC that I've ever read, for one reason: They don't know the OC from Adam.
Criminals know cops. They also know off-duty cops almost never OC. None of the many people who asked if I was a cop was a criminal or the criminal type. In fact, nearly all were neophytes when it comes to guns.
When a criminal sees a person OC, particularly if they observe the individual is maintaining an easy but alert awareness of his surroundings, they don't WHAT or WHO they're dealing with. Could be some Joe Wannabee. Could be a former Special Forces operative who's a nice person but well-prepared. Could be some lady who spends weekends at the range practicing with and learning from the best of the best of the best and absolutely will mow down any attacker with swift surgical precision.
Criminals don't like unknown situations any more than anyone else.
Case in point, a couple of criminals and their entourage of friends who crash my apartment complex pool back in 2009. Short story, they tried walking off with my sunglasses and towels. I stopped them. The big, 300-lb badass tried pushing me around and wound up flying ten feel to land harmlessly in the pool, but he got the message: It doesn't matter how big or strong you are, you're not going to win. He exited the pool, leaving the sunglasses and towels where he dropped them.
He didn't know me from Adam, but because I was not armed, he sized me up and figured I was a pushover because he outweighed me by 70 lbs and was a good three inches taller.
Had he encountered me in a different situation where I was OC, he'd likely have thought, "No way" and moved on, a likelihood supported by crime statistics.