Matt,
I think this is the situation you are referring to, right?:
http://www.thehendonmob.com/tournament_director/verbal_action.htmlThe circumstances there were (arguably) significantly different than the hand being discussed in this thread. In your 2002 WSOP hand, Rosenbloom was facing action; the hand had not reached showdown. Rosenbloom could either call or fold. He made a verbal declaration of his action. And enforcing that verbal declaration seems pretty straightforward (even if the circumstances made it a difficult ruling).
In the hand being discussed, all action was complete, and showdown had been reached. Neither player had any action pending. They did not have the option to check/call, bet/raise, or fold. Well, at least they clearly did not have the option to check/call or bet/raise. The crux of the debate (or at least part of it) is whether they had the option to "fold" in the same sense as when action was pending.
If you believe that the option to fold/muck at showdown is the same as the option to fold when facing action in a betting round, then a verbal declaration of "fold" should be treated as binding in both cases.
On the other hand, if you believe the option to fold/muck at showdown is merely a courtesy extended to players who don't want to reveal their losing hands/bluffs and thereby speed the game along and keep emotions in check, then with no action pending, there is no action that can be verbally declared, and the (tabled) cards alone determine the winner.
The TDA rules are not 100% clear on this issue, but I feel that Rule 8 ("Cards Speak") suggests the latter -- i.e., saying "fold" at showdown is not binding, and the winner is determined by the tabled cards. I prefer this interpretation.
The second issue -- and I think it should be addressed separately -- has to do with determining when cards are validly "tabled" to be eligible to compete at showdown. And the main question is: does intent matter? If intent does not matter, then any cards that get face-up at showdown -- no matter how -- can compete for the pot. If intent does matter, then if there is a dispute, the TD will have to make a determination based on the totality of the circumstances (including the player's verbal statements) as to the player's intent, and if it is determined that the player intended to muck and not table their cards, the TD would rule the hand dead.
I prefer the interpretation that intent does not matter, so any face-up hand at showdown competes for the pot no matter what. It's a cleaner interpretation which does not depend on a judgment call from the TD as to a player's intent. But either interpretation is reasonable.
If the TDA's goal is consistency in all tournaments, you might considering clarifying these two showdown issues in the next edition.