Very much so.  You only have to look to the volumes of merits the merit sources gift each other, or, to those they are trying to give a helping hand to rank up (instead of letting the system work as intended).  Another one to look at are the merit sources who willdump seven or eightmerits to nearly all users (because they can't find enough posts to merit) then dial back to just one merit to those they are in despute with.

...and it's not just "useful" posts that are showered with merits either.