Top AS Offenders causing RFC-1918 DNS traffic

Based on a recent presentation done by KC (Caida) here is a URL to the " 20 AS's case more than 50 percent of the RFC1918 PTR updates" http://www.caida.org/outreach/presentations/dns0209/mgp00025.html It would seem that folks like 4134 3352 7132 5673 5676 (top five) could mitigate this traffic with ease.