[potatolicious]

Or you do it the same way everyone else does it when the rules change: everyone who already has Banned Thing is grandfathered in but it's no longer transferrable or acquirable.

Or you do it the Valve way: give everyone the Thing and make existing Things the Extra Special Limited Edition Thing that's functionally identical but still confers bragging rights - this would still be within Mojang's rules.

[Avenger42]

#1 is probably easier, but #2 is probably a better user experience. Either way, you're right in that deleting the item wouldn't be necessary.