What happened in the OP really wasn't a brilliant idea. Comments like that will catch more grief no matter what level you work. When I have a late game situation similar to the OP, I hold my comment till I am ready to administer the throw-in. Before I blow the whistle, I tell the players three things: 1) be aware of the plane (to the idiot who may not think twice about it when defending the throw-in); 2) hold the spot (to the thrower); and 3) play the ball (a hint to the defense to make it a "clean" foul if possible). Never had a problem with number 3. If you're wondering, I do take a little time with the late game throw-ins because taking one's times avoid situations that bite us in the arse later.