King Headset scoring: fact or myth?

Scout

I'm sure other headsets will cause the same mark.

Chris Kings are uniquely designed different to other headsets. The scoring is a result of the flex that is allowed by the "o" ring present in the CK design. This is not possible in standard "aheadsets" as they have a metal compression ring which locks the steerer tube in place wrt to the headset bearing inner sleeves (…assuming they are correctly fitted and adjusted)

No Marks
Yes frame was faced by builder
Carbon steerer.

Yes
Yes
Steel

my CK headset has been on a number of frames and has had coil Revelations , Pike 409's, Fox 36's, Magura Thors and now has coil 454 Pikes in it.

I've never seen any scoring on any of the forks but did see a tiny mark on my 409 Pikes but would have hardly been worried by it.