If you wanted, you could get away with implementing these if you add a cheat code. For example, the first guy in the training dungeon; after you find the second staircase down (or any arbitrary action, really), it could trigger him to offer the option to enable and disable joke items.
"You know, in the end this is all fun and games, really. If you're feeling really silly, I could allow game-breakingly powerful joke items for you. Just accept this quest to enable, and complete it to disable."
I'd have to explain "Annoying Twerp" status if you did, though. It was the balancing aspect of "Shield of Lies."
For each monster type blocked by Shield of Lies, there is a 50% chance that monster will "quit." That is, disappear and no longer be spawned by the game (You're cheating! I quit!). The Goblin King will quit if Goblins, Goblin Captains, or Goblin Shamans quit.If the Goblin King quits, the game is unwinnable.