Ask HN: Will Chromebook delete all your local files without warning?

After all of my locally-stored files and some of my login cookies went missing (and my laptop was perceived by at least one site as a "new device") I found from searching that the ChromeOS thinks it's fine to destroy this info, with no warning, if it feels it can't run properly. I didn't know this and I don't find it credible. Do you know?

I have never put it into developer mode, this is pure ordinary consumer chromebook.