I assume you mean those lower-ranked members can be trusted with sMerits if they have a history of....something?  Even if that were true, most Newbie/Jr. Member/Member-ranked users haven't gotten a lot of merits to begin with, so they don't have a demonstrable history of using the merit system appropriately.

I'll admit I know which Hero & Legendary members tend to make quality posts, but I try not to merit them often, and if I do give them merits, it's usually a small number.  I do try to save merits for lower-ranked members, and I love it when I can help a deserving individual rank up.

But every merit source is different in their approach to the "job", and I'm not sure how much can be generalized about them as far as who they distribute merits to.  One thing I think is true is that there are a number of them who actively help members rank up.  The problem is--and always has been--that most Newbies and Jr. Members post complete crap.  There are exceptions of course, but if you're wondering why most members of those ranks aren't receiving tons of merits, that's the reason.