Appreciate the comments. I tend to agree, overall. I didn't see the hand, I was playing at a different table. Here's an exerpt from my website, which had links to the "official" rules, the TDA rules, and had about 15 quotes of specific rules that are routinely broken at the games I play in. The site was set up specifically for this one game, all players had used the site to register and I referred to the site as the "official rules" on many occasions in email correspondance in regards to the game:

"""If a player mucks their hand, their hand is dead, no matter what. That means if there's a 5-card straight on the board that one player doesn't see and the other player announces "I have a straight" (which both players do, since it's on the board) and the other player DOESN'T SEE THEY ALSO HAVE A STRAIGHT and mucks their hand, that hand is dead and the pot goes to the other player. No hand will be brought back from the muck at any point in this tournament. It's imperitive that players keep a level of awareness of the board and what cards they hold. For players less experienced at poker, it's recommended they simply turn their cards over at the showdown and let the table declare the hand. Once again, though, ANY PLAYERS HAND MUCKED BY THAT PLAYER IS MUCKED AND NO LONGER PLAYABLE, NO MATTER WHAT."""

To add another wrinkle, we also had taped "betting lines" in front of each player position and established that any hand is dead if it is placed in front of that line.

I told everyone to read the "house rules" many times in the run-up to the game, and had a copy of them on-hand the day of. I put that rule in mostly to protect the newer players, who can't always see hands, and to try and prevent commentary about the board and what hands are possible, etc, while the hand is in-play.

These overly specific rules were mostly due to the one group of really bad players who were for the first time learning what a string bet is, being forced to act in-turn, etc. The 2 guys in the hand were not part of this group of newer players, but since the rules were SO specific, I felt there was no choice.

Incidentally, the player who made the mistake acknowledges that it was his fault and it was a very expensive lesson, and he took the ruling with no argument at all.

But I also feel(along with almost everyone who replied to the post) it was the wrong ruling... I just didn't see that I had a choice in light of how specifically that rule was spelled out for this game, in an effort to prevent clashes with the newer players and the more experienced ones. I felt I had to do this, since I myself was playing, and didn't want to have to use "judgement" to decide any issues when it might be taken as manipulating the circumstances in my own best interest.

One thing's for sure, though. I bet that guy never does that again...

And for me, I think I'll keep my games to STTs where the entire group is on the same level and there's no need for such considerations beforehand that might end up working against "the spirit of the game", as was the case here. Ultimately I believe it was my rules that caused the problem here more than anything else. I tied my own hands by trying to create a plan for every possible scenario.