I observe two different matters regarding scorekeeping and queue managing here.
One is a need for not having the queue being a stand in line, players self maintained, queue. And the other is making scorekeeping easier and having less errors. It is apples and pears, really. But can go hand-in-hand in a more automated queue system.
People say "just have player penalties". But remember this has to be air tight and correct each time. Or it is more heat on the scorekeepers (volunteers, little pinball experiences, ...).
People walking off games in a tournament where you are obliged to sign off is just unacceptable. We know why - people are upset about the outcome of their game and need to steam off. It just causes errors to happen. Delays at best.
A solution of this, still in a more manually run setup, is, that the players will have to hand in their badge before a game is started for them. And it is only returned to them upon signing off the game as either score or void. No badge by scorekeeper at game over - no valid score. No badge to hand in - no games started. Badge for a game still by scorekeeper when next player steps up - void the score.
Another suggestion to ease off the pressure from scorekeepers and the stress at qualification deadline, is to freeze the queue, say, 15 minutes to deadline. And determine, that the X players at the top of the queue is granted to play their attempt. Even if one or more will have to start their game past deadline. And no more, even if all games happened to conclude before deadline. The X being set by the TD. Again, not the responsibility of individual scorekeepers.
Just personal experience as both player and scorekeeper (I am sure PAPA has turned every stone and looked under them several times).