Nothing.  Awarding merit is not moderated, the mods don't have time or the inclination to deal with that as a headache.  Also, awarding merit is subjective, every one who has received merit can give away their sMerit anyway they wish, within reason.  I'm not a merit source, but I can only assume the same holds true for them.  No body is looking over the merit source's shoulder to make sure they are giving merit to the "right posts."

Then there's this: