This makes me think of the HN link yesterday about identifying businesses that are doomed to fail because the only way they can sustain themselves is moving into new markets. If Google keeps on banning publishers from hosting AdSense ads in order to keep the AdSense money, that's the same dangerous behavior that's indicative of an unsustainable business. The question becomes can they sustain the growth and movement? Are there enough new publishers for Google to sign up to replace the ones they arbitrarily ban or will they eventually start having a hard time finding publishers and web properties?