While I don't have examples of this happening, and don't really have the time to try to research this, we are trained on what to do if we come upon an active shooter situation. We are trained that if someone in plainclothes is in the act of shooting a gun or is armed, does not have anything identifying him as a possible LEO (badge, hat, duty gear) or does not immediately yell tou that he's a cop, you treat that person as a threat. That means you disarm them, cuff them, and then search for ID. In our use of force policy, if we feel that ours or someone elses lives are at risk, we do not have to give a warning and attempt you to put your gun on the ground before we open fire. What that mean, is if I am coming to the scene of a shooting, and a CCW holder is there with his gun out, does not immediatley follows my commands and disarm himself, you will get shot. While I agree that chances of this is slim, it can happen. It's the same a "friendly-fire" incident in combat. Stress is high, there is a lot of confusion, and decisions need to be made immediately. With something as big as Airventure, with a lot of people, an active shooter can cause widespread panic. Responding police will have enough on their hands without trying to figure out if you are a CCW holder or the threat. It's not worth the risk. While someones intentions may be good, situations can go south very quickly. There is too much risk to yourself and the public. I work in plainclothes all day, everyday. Me and a partner were working the streets one time when we saw some marked units roll up to a house. Guy in front started running, uniforms gave chase, we (in the car) drove around the block looking for the runner, he was running between houses. When we saw him 3 blocks later, we jumped out to help. At that time he was tackled by a uniform and 2 others were coming behind. One uniform saw us running up, put his hand on his gun, and started to confront us. We yelled out we were police, and lifted our shirts so he could see our badges. Could the situation gone down differently, yes. And not for the better.