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.
exactly
the ad networks are just middle men really providing a service between advertisers and publishers. if publishers dont like the ads showing through the network then they are free to stop using them.
if you expect coinad/coinzilla/a-ads/cointraffic/mellow etc etc to make judgements about every advertiser that comes along, whether they are possibly a scam or not - then its really not going to work
i cant believe for a minute that they are involved in any scams
the simplest explanation is usually the correct one - the owners of these investment programs probably just use the ad networks themselves to directly promote their service