Two problems with this: First, some people can't seem to be trusted to choose a tag that doesn't violate the CoCs. Second, [i]if[/i] Bungie were to sell name changes those individuals would very likely buy another, make the same dumb move that caused the issue in the first place leading Bungie to 'Guardian' it again. Then they'd accuse Bungie of theft since they would've paid for it. A game tag doesn't affect your gameplay so it's simpler to just allow one.