Let me ask you this:
With literally millions of hits sold per week put together from all these bulk targeted traffic sites, how come you can spend all your days surfing the casino scene and speaking to other affiliates and site owners and no one has ever seen a single one of these popunders?
How come not a single one of these resellers can tell you even one site where the traffic runs?
If this is traffic at all, it is raw traffic. It may be that they used to run the raw traffic through one of their own portals and when it comes out it is magically casino traffic.
But with the proportions this epidemic of bulk targeted traffic has now, I think they are not even proper hits but computer generated ones.
There is no way that these could possibly be real without being noticeable all over the place.