Coaching box, if that is what allowance you are giving him, ENDS 28 FEET from the end line - unless your State has given some further latitude or other direction as to placement of the box.
In my opinion the coach should never be in front of the scorer's table. To cross the division line means he has assuredly left his coaching box and proceeded to, even if momentarily, restrict the view of the timer/scorers.
You are right Drake, stepping outside the rules in an attempt to be a good guy can very quickly backfire. Intentional abuse or making up his own set of rules "Am I bothering the game?" needs to be immediately rectified and further abuse should be punished.
Here is the rule coach. Your box is back here. And you have stepped well beyond its limits into the realm of Technical Fouls. You need to get back to YOUR bench.
I would not have stopped the game to make this correction. I might have ran nearly ran into the coach as we switched ends of the court and said, "You need to get back to your bench." or "Are you lost little boy?"
The game situation should not effect your decisions about blatant violations. Blatant violations should be punished. I wouldn't have liked to do it but would probably have T-boned him with the second violation.
The answer is "Yes, you are bothering the game! get back to your bench." His position was distracting you from your work.
JMHO