I'm inclined to believe this, but I'm skeptical of Google Analytics numbers being deflated. Wouldn't people notice the data not being consistent with other tools or their own web server logs?
I've also seen on many SEO forums that people have complained about the same things in regards to getting banned days before their payout.
Most website advertiser types are the kind of people who are recalcitrant to file a lawsuit. I know I am myself. So really, it's a good business decision in this regard.
I can't accuse Google of anything though. On the other hand, automating account bans past a certain earning threshold unless they're high profile people seems easy to implement, with a massive earning when done on the multi-billion-dollar [0] ad revenue scale that Google oversees.
[0] http://www.adweek.com/news/technology/google-finally-crosses...
More earnings than not banning them and letting them continue to make money for Google?