Jasper,
This is from Robert's Rules:DEAD HANDS
1. Your hand is declared dead if:
(a) You fold or announce that you are folding when facing a bet or a raise.
(b) You throw your hand away in a forward motion causing another player to act behind you (even if not facing a bet).
This is for cash games, but it would apply to tournament poker if the dealer did his job properly. That would require the dealer to get the cards from the player that announced he is folding, and mucking the cards before taking action from the next player.
Likewise, when a player tosses their hand away, in a forward motion, the dealer should kill the hand before moving to the next player. This can get a little tricky if the dealer recognizes that the folding player thinks he has won the pot, but there is another player in the hand. In a case like this, the dealer should offer some protection by keeping the hand from hitting the muck and returning it to the player. IMO, this is in the best interest of the game.
These actions MUST be taken or, any hand (technically) can be deemed live until it is in the muck. A little complicated but a good dealer eliminates the need to even call for the floor.
I've considered requesting a slight change in the wording for TDA #34 Verbal BETS in turn are binding would be more appropriate than Verbal declarations.... The word declarations is more suited for TDA #10.
I hope I'm not drifting too far from your question but, like so many other situations, nothing has a simple solution without explanation.
POKER ETIQUETTE (Robert's Rules)
The following actions are improper, and grounds for warning, suspending, or barring a violator.
Reading a hand for another player at the showdown before it has been placed faceup on the table.
IMO, there are two ways to comply: face-up and on the table!