Earlier quoted context omitted.
What is disturbing is the reason they give for why they will do it. One thing is if the drive is specifically used for cyber attacks and other malicious operations over the internet, but they refer to these rules; https://support.google.com/docs/answer/148505 and they are extensive to say the least. On top of that this is yet another move from Google to declare their rights to control your content and access to it if…
sorry, maybe I misread your question. Did you mean to say that they already did this without any notice to users, and the only change now is that they will start to send notifications when they do?
The only change now is that the file gets unshared, you get a notification, and can try to dispute the claim. This is a strict improvement.