Obviously, you are NOT to verbally mention to a player or coach that you are doing this. In my opinion, you weren t. You have the flag and you can control it. You should not officiate for ratings because I can assure you when you ignore the calls, you get rated lower. Also, you should enjoy officiating and being constantly criticized and tolerating it is not enjoyable.
Coaches measure their behavior, or lack thereof, by looking at the list of penalties.
If they receive none, they have been behaving quite well. Under no circumstance is any poor behavior by players to be uncalled. Incidents of taunting are increasing as is the use of poor language. Call the fouls. The NCAA wants officials to make sure all players wear mouthpieces at all times.