Originally Posted by Estie
Another effective and less stringent anti-scum option is disconnected stairs - if only it was less "gamey" a solution...
Random idea: how about one-way-connected stairs? If you go down a set of stairs, the staircase remains to use as an escape route, but if you go up, "Morgoth's magic seals the way behind you" and you have to find a different down staircase to get back down again. That way you can always retreat back to a higher level if you get in trouble, but you can't just sit on the same staircase and scum up and down indefinitely.
Alternatively, for a less "gamey" but harder to implement solution, you could save the previous level and take note of which specific staircase the player enters by. If they leave by that same staircase, they just get returned to the saved level; if they use a different one, they get a new level instead. So sitting on a single staircase and scumming will just flip you back and forth between the same two levels indefinitely, but if you return to the previous depth via a different staircase, you'll end up somewhere new.