and some users are going to permanently lose data
Why couldn't you write code to let users compare and choose which version of the data they want to keep?
Why couldn't you write code to let users compare and choose which version of the data they want to keep?
What will the users do for 6 months waiting for their data to return?
For some files (anything encrypted, for example) this may actually be the best you could do.
Dropbox had this behavior ten years ago, so it's kind of inexcusable for Google today to be just mindlessly overwriting.