How big is the coaching box?

[Stat-Man]

In 2001, my college alumni were invited to fill in at a college summer league. For some of the games, I kinda assumed the rolse as coach, since it was obvious i wouldn't play much.

In one game, I'm coaching, and wouldn't you know it, the other's team coach comes down and starts coaching in my coaching box.

He did this a couple of more times, so I figured I may as well join the fun and coach from his box. When I do this, the one referee (who was the host school's head coach) tells me to get back into my box. I let him know at the next dead ball that if we were going to enforce the technical points of the rules in a summer game, he needed to tell the other coach to stop tap dancing his way down to my box. Referee told the coach something, and I got a dirty look from said coach, but i just looked at him and shrugged my shoulders, as if to say "What did you expect me to do?"