I've got a wizard's lair coming up for my players, and that both directly and indirectly prompted some odd potential Leaving spell questions. They center on the "barrier" aspect of Leaving, and "A barrier is anything he could not physically go through; a closed door is a barrier, a pit is not."
Scenario 1: There is a Feel Illusion of a wall across a hallway. Is that a physical barrier? It has to be violently struck to dispel, so is it any less of a barrier than an unlocked door or a wall of paper?
Scenario 2: There is a Sign of Fear across the hallway set to trigger if anyone crosses the boundary. If someone Leaves from one side of it to the other, do they trigger it?