I commonly see one good post from a user, and then go through their history to merit even more of their posts, because if they have made one constructive post then they've likely made more. You can go through my merit history, and you'll see that I've done this a lot for multiple users of all kinds of ranks. Even, some of the highest merited users on the forum.

Especially when it comes to newbies. I think users are a little more willing to give merits to newbies who have made an effort with their post even if lets say a hero member made the same post, and they wouldn't have got merited for it. I think its in the nature of a lot of users to encourage newbies as much as possible.