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.