I used to work at Google on stuff related to account bans.
Global bans are not new. They were standard a decade ago. The reason is due to the structure of the various spam/abuse industries that plague any service that allows user generated content. What happens is this:
1. Accounts get harder to create as signup security improves
2. Black/grey-market account sellers come in and start creating accounts that get bought by spammers/fraudsters.
3. Spammer/fraudster abuses an account on service X, it gets locked for service X. They sell the accounts _back_ to the seller, who then resells the account once again with a note that it can't be used for YouTube or whatever.
4. Different spammer/fraudster buys the account, abuses it on a different service, goto step 3.
Their systems have some notion of why accounts were suspended or blocked, and the tech does support individual service level blocks. But they weren't used much back then because the pattern of a user being bad on one service and then being bad on every other service was too strong.
The problem of false positives was well known a long time ago, and the noise:FP rate is very good - if a script accidentally disabled good users with even quite low volume the people in question would be on Twitter or HN within hours making articles like this one, which did get noticed. So false account blocks were pretty rare.
Back then and still now, I think Google need to make it easier to handle this situation. Strong end-user support in these situations is hard because genuine fraudsters will happily file support tickets and socially engineer support to get their accounts back - I even witnessed auto-generated pleas to support once. They were quite convincing individually, only when you saw a few thousand of them with re-arranged sentences all begging for help with identical language was it clear they were spam. However they could still make it a lot easier, and in particular, could improve Google Takeout to be easier to use (e.g. automatically uploading the backups to various non-Google services).