Geesh. Ya know, I wondered sometime back if something like that could happen.
"I hate so-and-so, and I'm gonna click 'em right off the page!"
Glad you are fixing the problem. Limiting clicks by a single IP is a grand idea.
Some people might not really know that those are pay-per-click (credits represent money). I certainly didn't until I had one myself.
Now that I know that (here is an idea for other nosy people who want to be kind...)
When I'm doing nothing more than being nosy as to what a thing is, I will see if the website is right on the banner anyway and type the URL in myself so that real potential customers are the ones who use the clicks.
Nessie