I see it as this too, If they are a leecher, joined this month or 1-2 months before, i see them as scammers, they might not be, but I see them as, becouse the always come with like a level 138, In my head, i think ' That's a recover acc'..
If they are Forum addicts that join atleast 6 months ago, i feel pretty much they're not a scammer, and not a spammer aswell...
Guru+ i often trust, but only 4 months + there too. Post count does matter some times i think. But Vouches, do they? Yes some I think acctuly.. I feel safer trading with Skele_master then with a random leecher, lol. Or someone as... Trip_fagex? i think he got like 30 vouches and is a apprentice ^^, I do feel safer trading with them