Happens more often than not. It's our hesitation to use force that gets a lot of us hurt or killed. The Dinkheller vid is ample proof of the worst case scenerio on that.
Despite what a lot of people on this board think, I don't know any LEO that can't wait to use force on someone. It's a big pain in the ass. The paperwork, the supervisory inquiries, the MMQB by EVERYBODY.. huge pain. I've found that the sooner you can interdict with an irritant gives you a decisive edge even if it doesn't force compliance. It takes some of the fight out and makes it more dificult to see you. It delays their reaction time and can give you time to formulate another response (IF you've allowed a reaction gap). People get hurt when it turns into a brawl. We should be fighting smarter, not harder.