The title of the thread is
I personally have experience with high quality content sites AND auto-generated sites that are just a bit higher quality than scrapers. (They don't use serps for content)
I also send traffic to affiliate programs from both types of sites. The ROI is about the same and the CTR for adsense is actually 2% higher on the auto sites. From this quantitative evidence, a visitor from a scraper has a similar ROI than a content site. Thus, Google allows them to exist as long as they don't hurt the advertisers. Googles aim is to provide high ROI for their advertisers AND the greatest reach.
If you care about brand name, then maybe this is a concern. But if you only care about ROI, then it shouldn't matter where they come from, just how they convert.
Blend27, just curious. How do you know that you actually got 17 scrapers banned? Does Google actually reply to you?
I think the liklihood of receiving click fraud is much higher from the content network than the ad network for obvious reasons. If you are tracking and seeing lower ROI, it's most likely from click fraud, NOT scraper sites, from what I've seen.