What does it mean when a player throws his card protector to the center of the table when the action is on him during a tournament? Can this mean more than one thing?
As a dealer at a local bar for 40/60$ tournaments, I would consider a player throwing in his card protector as a motion of betting... without any verbal statement, it would count as a bet or a call if another player has bet that street already... This can also be classified as an illegal forward motion especially if the player is looking toward his opponent while throwing a value less item on the table... the final decision will vary according to every dealer/house rules and should not, unless it is said verbally by the player, be counted as an all-in bet (although I have never dealt bounty events, in which case the bounty chip idea posted before would make sense)
Some tournaments offer a bounty. Each player gets a bounty chip, that goes in the pot when the player is all in. If the player throws his bounty chip in it indicates that the player is all in.
That might be what you saw happening. As far as card protectors go, they mean nothing except that they protect your cards. Of course there may be some new rule someplace, you should always ask where you see it happen. There is no official rules of poker that apply everywhere, you need to ask were you play for rule clarifications.