Our guess is that this extra quality assurance step will not reduce participation in the Google ad network of websites. Although it will be an annoyance to publishers, the real potential killer for Adsense is it's low commission percentage. This extra step may have some impact filtering out lazy, poor quality publishers and some offensive content websites as well. Overall, it is a good idea to make strides to improve the quality of websites within it's ad network--despite the inconvenience. This step could also help reduce the competition for quality ad inventory, if you look at it from another perspective.