The Forbidden Journey queue in general is very flawed. I've seen single riders hopping into the middle stand-by line. Stand-by line guests hopping into the express line starting from the Dumbledore room. Guests having the ability to skip the entire outdoor queue if they don't have a bag (essentially being penalized for having a bag). If you're a party of two in the stand-by line they will hold you off to the side until they find another group of two to pair you with for the four person vehicle. Those magnetic queue chains always fall off from people messing with them and they aren't always put back so guests will get confused and follow a queue path they aren't supposed to. Probably the most annoying thing about the queue is that doorway from the ride exit stairs and the sorting hat area as guests will sneak back in line when TMs aren't looking. Also, as
@12th Man pointed out, the line after guests are paired to board the benches is way to short for the speed at which the ride moves and this is what stresses out the TMs. Overall that queue is neat but really stressful from an operational standpoint.