If you have a forced vacation period, your employer is auditing your emails/drives/devices. It's perfectly understandable that they search your work assets regularly (and randomly) as espionage happens. They probably mentioned they would do this at some point long ago.

Yadda yadda, “what if” argument. The context of the parent post is obviously not a “force majeure” situation but a more damning frisk, hoping to find enough to fire the man and sue him into bankruptcy... sleazy

How would you even know that the company searched your corporate OneDrive account?

In the USA they dont have to tell you when they do, so it might have happened already and you'd never know.