I believe the ruling is to give the dealer the instruction to kill the unoccupied seats cards immediately instead of waiting for the action to get to that seat. Example; absent player in two seat is the big blind. After dealing down cards to all players, the dealer kills the absent big blinds hand into the muck before the UTG player even acts. There used to be some tournaments that would deal absent players in and if they returned before the action got to their seat, they were allowed to continue playing the hand.
There was a ruling that we used in cash games, when suddenly, smoking was not allowed in poker rooms. The ruling was written like this: Players that are dealt a hand, must be within "earshot" when the bet gets to their seat, or their hand is dead. I can remember players running from the smoking area yelling " deal me in, deal me in." or " here I am, here I am."
Nick C