So, I continued to watch him.
Today I covered biology. They had a test. This one boy was doing all the things one shouldn't do during a test: talking to a neighbor, looking around, and acting like he was going to do something inappropriate. Of course I was watching him.
Eventually, he settled. He got to work on his test. And I turned my attention to other things.
One of these days they'll get it. As long as they're complaining about me watching them, I'm going to watch them. The minute they get to work, they won't even notice me, and I won't have to keep an eye on them.