On the contrary it's now difficult to know users that are building accounts in order to earn. Besides those who are more interested in learning than earning will in the end still wear paid signatures. Before now, how to easily identify those who are only interested in earning is through the bounty. But now their attention is shifted to signature campaign, hunting for 100 merits.
I don't think anyone needs to study an account history before replying to a question or sending a merit. If the post worth merit then send merit without looking for who is behind the account, if the discussion is interesting then response it. Policing every account and trying to find fault in every forum account is just bad. It's pointless, makes the whole thing wrong about the concept of a forum. Obviously if something comes up undeniable truth then change your mind.
Keep it simple. Share knowledge and seek.
Its really funny you pointed this out so plainly because this is exactly the habit of some specific members here in the forum of which I won't mention but so forum members are found doing this exact act, I mean whats all the fuzz about, is it really necessary to check someone post history before given a merit, if the post is worth meriting its best you just merit it and move on.