Many (or most) coaches are paranoid. Even though I know most of the HS coaches, there is some turnover. I'm afraid that I would call one of them by their name and not remember the other one. If you don't think they notice stuff like that, you are wrong. Many of them are constantly looking for a reason to justify their paranoia towards officials.
At the college level, I sometimes have never met a coach before. I don't trust my ability to remember that coaches name all the time. So one thing that I know will work for me every single time is to just call them all "coach."
