Dissecting your three examples.
In the first case, (and based on their own statements) those people were buying up phones by the hundreds, shipping them to a single physical address and then scalping over the internet.
It's basically fraud. So yes, they probably got picked up by an automated algorithm that looks for hijacking/CC fraud or bot-nets.
From public statements though, I believe most of them got their accounts back when they reached out to confirm they were real people and not some fraud bot-net. It's still technically violation of their ToS, but I won't comment on that part.
The second case I'm not directly familiar with, and there's no public statements so I won't say anything further.
In the third case, the affected customer made a public statement afterwards:
https://twitter.com/salilstatistics/status/89986397181723852...
I can't comment any further than what's been said publicly except on general principles 1. Google does a lot of things to protect users from external attacks, everything I've seen seems to indicate they really do care about users, and 2. There are pretty clear ways to get back into your account should anything happen (https://accounts.google.com/signin/recovery is your one-stop shop), and 3. The user doesn't carry any ill-will towards Google once he realised what actually happened.
(Disclaimer: I work for Google, but the above statements are my own and do not reflect those of my employees).