As posted before, if you have an "old style" light bar, it's quite easy to fix it so it will certainly never damage the fork legs.
Mind you, there have only been two or three cases of a scratch on the forks. It must be some unhappy concurrence of tolerances. With most light bars, nothing has happened.
The possible contact spot is quite small. You can find it if you turn the front fork to full lock. If you take off a few millimeters of metal with a file there, at the bottom of the light bar, you're done.
The approximate location is shown in this pic.
If you take off some metal there, it's fixed and completely invisible, as this part is under the beak.
Sorry about this, it should never have happened. To be on the safe side, please take your light bar off and use your best file for a minute or ten.
Cheers,
Michel