Since none of the two networks have any kind of action tracking for advertisers, creating a ref for each network seems like a logical thing to do.
It is most likely the HYIP platform itself that use such a ref, when they first launch.

Both Coinzilla and Mellowads seems to have a rather high ethical standard, so personally I find your theory to be ridiculous to be honest.

Theoretically you don't know if a program is a scam, before they actually scam. For the networks to turn down such advertisers would be bad business.

Even Google run these kinds of ads.