I've always thought that flagging someones comment meant that you are trying to get it noticed by a moderator to show them if its good and deserves a merit or if its bad and has foul langauge. is it one, the other, or both?
As mentioned, mods cannot see it, not, so urgent matters should be taken directly to a mod instead of flagged. Besides that, do not flag comments that should be merited, because it most likely will be deleted instead; it is abuse of the flag function as well.