Score discs when replacing brake pads?

[tyl604]

Does anyone do this? I saw a video of a guy replacing pads on a ML320 and he recommended scoring the discs with sandpaper.

Is it necessary or does it help?

PS - I posted this question on the ML part of the forum and expected to see it in my typical "New Posts" list but cannot see it unless I go to the ML section. News to me. I thought all posts went to everybody when they hit "New Posts."