Nick -
I agree that open folding is a stupid thing to do. But are you saying you don't allow it?
Frankly, if I was a player who lost a hand to a player who had attempted to open fold, I'd be quite upset. I'd be equally upset if I lost to a player that was prevented from mucking a card.
If you do not allow open folding, then I think we've come to an impasse, and we must simply agree to disagree (even though I hate that phrase).
If you allow open folding, I gotta ask, how is that different than the player who shows one card and attempts to muck the other?
Action is pending: Tableing the second card!
Correction: Action is pending. Tabling
OR MUCKING the other card.