And what will he do about the hundreds of "RealStephenKing" "OfficialStephenKing" "StephenKingTwitter" accounts that will spring up and start scamming people and linking them to fake websites? How much will that cost Stephen King?

If that becomes the norm then people will probably start caring a lot less about twitter posts in general.

How much will that cost Twitter?

And if Twitter’s user experience degrades to the point where King can’t Tweet effectively without a blue checkmark, then the platform is deeply screwed.