3 in, 4 out

[Adam]

Soph girls tonight. V-team is losing by 40+ in the 4Q when coach sends in 3 subs during a free throw sich. 3 subs come in, 4 girls go to the bench, leaving 4 on the court. Partner and I both see it, but decide to let the situation play out.
After H-1 makes both free throws, V coach realizes the problem and sends V-5 running onto the court while V-1 is bringing the ball up the court.
Partner blows his whistle, and comes over and we discuss the situation. Partner calls a T for sub entering without reporting. Coach argues that she was not subbing, since she had not been subbed for.
My thought is that, in that case, it's a T on the player for leaving the court unauthorized. She'd been sitting on the bench until the coach realized what was going on.
I was inclined to let it go, but my partner was right. Thoughts?