Whenever a new feature, like merit or the feedback system is added, it takes the community a few weeks or months to figure out what is or isn't acceptable. I'm personally of the opinion that merit issues aren't related to feedback, and you shouldn't get negative feedback even for "abuse" of the merit system, whatever that ends up meaning.
Its kind of a rough position to be in, but you shouldn't worry about it too much.
Ironically the merit system was introduced to try prevent people from leaving negative feedback on poor posters. It's a tricky situation to police but people shouldn't be allowed to trade merit or leave it for their alts as it's deceptive and defeats the purpose of the system in the first place. I can't really see any other way than negative really but users shouldn't be allowed to get away with it otherwise everyone will just do it. At least if there's the threat of negative for users caught engaging in it then most people will think twice about it. If there's nothing to lose by attempting to trade merit then the practice will become rife.