The rule I know with regards to awarding merits is that you have to give it to a constructive post. Constructive in my opinion varies from person to person as we all have our opinions towards what constructive is. What is constructive for me may not be constructive for others because they have different standards. So I guess, the responsibility and the call of judgement would be on the ones awarding the merit. I don't think mods would question your judgement, they are concerned however with exchanging of merits or merit farming for the sake of ranking up or getting bonuses from campaigns; but if proven that you are not guilty of such act, then you have nothing to worry about. Just make sure that the merit would be justified accordingly with regards tp the post.