In my old Amber campaign, Things in Heaven and Earth, Benedict, rather than losing an arm in his duel with… whoever in the books cut off his arm… was blinded.
Somehow, and I don't really remember how it happened, the players decided that the best way to help him recover his sight more quickly was to get him to walk the Pattern again. This was accomplished by having one of the players' characters (one with really high Endurance, I'm sure) walk the Pattern themselves, with Benedict sort of walking in their wake, holding onto their belt or something.
This was done.
It was quite exhausting for the player character. They got to the center, Benedict thanked them, and the PC had the Pattern take them out to the edge of the room, where their siblings and cousins watched.
Then one of the players said: "And then Dworkin shows up in the middle of the Pattern and teleports away with Benedict."
The room went dead silent.
And we decided it was just too damned cool not to do, so that's exactly what happened.
The next time they saw Benedict, he had the Jewel of Judgement embedded in one of his eye sockets.
HA! Oh, yeah.
I don't remember who came up with that stray thought (could have even been me), but it (and the result) was awesome.
Good times.
I think that might have been the event that led to the "If the players joke about it out loud, the GM can't have it happen" rule, though clearly we agreed to let it happen in this case.
That rule was in place before this happened, but I asked for an exception from the group so that we could allow this one. Everyone agreed.