SOP in this area of Oklahoma is to inquire if the officer is 10-12 (suspect present or in hearing range), or to advise that we have 10-12 information. Sometimes, if one of the officers has his unit radio on the PA, he/she will advise dispatch to go to another channel. It's all about officer safety. Suspect behavior is unpredictable, a perfectly calm suspect may go totally bonkers when he learns that the officers know about past "indiscretions".
One of our officers was on a Peeping Tom call one time, and collared one of our local punks at the scene. Roy was well acquainted with the suspect, and basically told him to come along, not placing him in handcuffs. BIG MISTAKE! He had almost reached his unit with the suspect when the complaining party came out and shouted "That's him!". The suspect suddenly turned on Roy and, knocking him to the ground, started choking him. Roy managed to draw his weapon and started striking the guy on the side of the head with it. He told me later that he was starting to lose consciousness, and had just decided he was going to have to shoot the suspect, when the guy finally let go, About that time his backup arrived (a neighbor called in an "Officer Down" and we dispatched everybody in the area!), they cuffed the a**h**e, and that was the end of it. But there was a major policy overhaul after that. Cuff 'em first, and don't give any prior indication of warrants, etc.
I might also add that this incident scared me half to death! This was back in the early Seventies, and handheld radios were not standard issue. In fact, we only had 3 Moto HT-220s for what was then a 60-70 man department. So I had no idea there was any problem until the citizen called in saying "Hey, the cop is on the ground and this guy is choking him!". I had local cops, SO deputies, university police and an OHP trooper all responding to assist. Hell, if the dog catcher had been on-duty, I'd have sent him!
Mark S.