I knew a person who used to spend $3000+ a day on Adwords who never got much attention from Google (reseller in the cosmetics niche). The only thing he mentioned is that at some point Google assigned him an Adwords account rep. He followed the advice of the account rep and got all the ads and keywords suggested by the rep banned. It would be funny if it wasn't so sad.

Eventually the person's main account was banned. Last I talked to him he was creating a bunch of fake accounts and running cloaked campaigns. It was much easier for him to be non-compliant on Adwords than compliant.