The first example - was basically fraud, that probably got picked up in hijacking/bot-net detection (based on public statements).
The second - I can't comment, as there are no public statements.
The third - the author made a public statement, and seems to harbour no ill-will to Google after it was explained to him what actually happened. I can't comment on that conversation, but I will say that in general, Google does a lot to protect its users from all kinds of security issues and attacks.