No if you download the local copies back then delete them from OneDrive, OneDrive will delete the local copies you restored to your computer. No because they would go to the download folder which isnt synced with onedrive.

users aren’t “Using OneDrive” intentionally

Yes this is the biggest issue with onedrive but its still on users to administer their system at the end of the day. That means doing the bare minimum research when removing something as integral as Onedrive. You cant just turn off a home directory sync service and not make sure your stuff has been downloaded out of that service.