After two USC fouls by the same coach, it's mandatory that coach be disqualified. However, any one USC foul against any coach, that is deemed flagrant, can merit disqualification. At some point, determined by the calling official, a single repeated sideline USC fouls may very well reach the level of being considered "flagrant".
Non-players are considered different than players, as adults are supposed to be more in control of their emotions than children, and are held to a higher standard.