That's already been implemented. With the shift to CPC, there are people who write that kind of software and sell to sleazy publishers. On the other side, ad servers have a fraud detection module that looks for those random clicks.
Sure, but those systems aren't going to flip out when each user clicks one or two ads, because that is what the normal data looks like.
You would get the publisher black-listed by e.g. google.
This would target the wrong people.