This is the way I look at it.
It's very difficult to become a Mod. Once you become a Mod, you don't want your name tarnished in anyway. Because if it is, then no one will trust you. When a Mod gives a yea or nea on a source, he's putting his name on the line. At that moment in time, the mod knows that the source is legit. Sources go bad. When they do, the Mods are here to help as much as they can. I would prefer to go with a source that is Mod backed than with a source that no one knows or a few vets know. Yes, it's very hard to become a Mod backed source, but not impossible. If you get a source from a vet, check it out with a Mod. If mod says yeah he's good. Order a little. Don't get carried away.