10 man lineup. In the bottom of the seventh, the DH is batting in the 4 spot. The pitcher enters the game and bats in the 6 spot for the catcher. The plate umpire allows this substitution (illegally, of course), and the visiting team says nothing. In the top of the eighth, the DH comes in to catch and the pitcher (who batted) remains in the game as pitcher. The visiting team says nothing, and completes their time at bat.
At the end of that half inning, the coach of the visiting team comes forward and says, "They batted illegally last inning - shouldn't there be a penalty?". The plate umpire then asks me (the base ump) for my input.
Since I was unaware of the situation up until this point, I said, "The pitcher and DH were locked into their OFFENSIVE spots when the pitcher batted for the catcher - if the pitcher bats for anyone else, he has to go." The home coach argued that since the problem wasn't caught at the time, and the DH and pitcher had played an inning on defense, everything was OK - it was too late to penalize. I replied that even though the visitors couldn't ask for batting out of order, the penalty of removal of the pitcher still applied, and we removed the pitcher from the game (to the dismay of the home coach).
Correct ruling?

It will be interesting to see how many respond to this posting.

The NCAA DH rule is one of the densest writings I've ever seen, and I've studied bankruptcy law and corporate taxation. If I understood it, I'd try to help.

Daniel 5:7

Yes. 7-2-c-(10) Penalty.

It sounds like they tried to make a legal substitution, but it was ill-timed. The DH can enter as the catcher, which terminates the DH and places the pitcher in the batting order in the former catcher's spot, but that change can be made only while on defense. 7-2-c-(1) AR 2.

They can't do that (even though your partner illegally allowed it, as you noted) while on offense. When the illegal substitute is noticed, he is always disqualified.

Now, a question of my own: would batting out of turn have been an issue had it been raised when the pitcher batted in the 7th? It seems to me that if the offense announced P batting for DH it could've been, but if that had been the intent the DH would have been disqualified, not sent out as the new catcher in the next half inning.

If the pitcher was announced as a PH for the catcher (as it appears to me in your post), or if no announcement was made, it seems that it would be a straight-up illegal substitution matter. Any thoughts?

Jim, you're right. When the pitcher came in to bat for the catcher, it wasn't a "batting out of order"; it was an illegal substitution. That means, of course, that it WAS a substitution, and the catcher for whom the pitcher batted was out of the game because he had been pinch-hit for. So, not only was the illegal substitute out of the game, so was the player for whom he hit. Thanks for your input.