If this wasn't a dream...

[Stat-Man]

I had a weird basketball dream and wondered what the appropriate ruling (any ruleset) would be if this actually happened.

I was an assistant coach for a team and during a time out in the closing seconds, the opposing team's coach came over to our huddle to listen to what we were planning to do to tie or win the game.

As soon as I noticed, I broke the huddle and started to make noise so to keep him from hearing anything. All while wondering "why aren't the refs doing anything? Surely they could T him or something."

I imagine this would easily qualify as unsporting conduct. But if it was me officiating, I'd be tempted to give a flagrant T and toss the coach since this so blatant.