I was once threatened by an ECO with a USC foul while I was a coach in the press box. The ECO was asleep, letting the clock run a number of times in critical situations when it should have been stopped. The first couple of times, I just yelled, "Stop the clock". But after I had enough, and he still wasn't reacting, I slapped the glass wall that was between us. Apparently, that woke him up, and he says, "If you slap that wall again, I'm going to call a USC on you!" You KNOW what I did the next time he didn't stop the clock.
And there was no foul.