Once you receive a warning notice, your site enters the scopes of the policy enforcement team. When you make changes to your AdSense code, possibly other relevant code on your site, they send human reviewers to reevaluate your site.
I believe this because I received a warning for encouraging unintentional clicks.
I received this warning because in-content ad units had links blended to site link colors.
Additionally, I was aligning ad units with images.
After making these changes, the issue was resolved.
They never ceased serving ads, which was nice.
This occurred around the 7-8k monthly mark for those wondering.
After making these changes my revenue dropped about 1/4. This was disappointing.
A few weeks later I tried to revert to the in-content ad units with the blended link colors. I tried to use a light gray background color, literally one shade away from white, to distinguish the ad unit from content.
Within 30 minutes of making these changes, I received two new warnings,
one for encouraging unintentional clicks, and another for having content over ads.
This is because I had a hover drop down menu for navigation that dropped over ads in some parts.
I made the changes and ad serving has continued.
I make less now, but as someone who depends on AdSense income to provide for my family, I am happy to continue serving ads in the first place.
The reason there is no competition is because everybody else is scared shitless to open themselves up to publishers.
Click fraud is a thriving and sophisticated business, and nobody else (major) has had the chops to explore that black box.
I found my experience with AdSense enforcement to be fair, but the process is frightening.
I am excited that Facebook is experimenting with their ad network.
Competition is good for everybody.
Any site that attracts a large number of fraudulent clicks is going to get their AdSense account banned. The site owner has no recourse if this happens to them: they agreed to it when they signed up in the first place - Google can drop them for whatever reason they feel like at any time.
Is it really that easy to put a gun to any random adsense user's head?
If you're lucky, you catch it, report it to Google & they just take the income away (as it should be). If you're unlucky, Google decides that you're trying to defraud them & their ad clients and kills your entire AdSense account for all the sites you have registered with them. A scorched earth policy being the best possible policy apparently.
If you get on the tor network, you should be able to find a few places where you can pay (for example) a $100 for 30,000 views/clicks from a random country in the world to hit a site.
I'd imagine 30,000 false adsense clicks would do it.