And what about when a notebook is encrypted?

And what about when a notebook is encrypted?

Or do these ideas fall under the category of "please don't roll your own crypto"?

I'd say so.

There probably are ways to defend against this though. Plus, AFAIK there aren't any significant known plaintext attacks against AES256 in XTS mode. And since this isn't a long-term storage situation but rather a short term one it's not like we have to worry about an exploit twenty years from now putting our data at risk.