What it means
In Google Drive, the owner of a folder and the owners of the files within it can be different accounts. Moving folder ownership to a new colleague does not necessarily make that person the owner of every child document.
A real-world example
A departing manager transfers a project folder to a teammate, then discovers a budget sheet inside still belongs to the departing account. The sheet may be affected when that old account closes.
What to do
Inventory important child files, check each owner and transfer them where appropriate before retiring the original account. Confirm the recipient accepts personal-account requests.
The distinction that matters
Work and school ownership changes follow organizational restrictions and may be handled in bulk by an administrator. Google states plainly that folder transfer leaves child-file ownership unchanged, so counting folders is insufficient. Audit the documents that matter individually before closing an account.
Google's file ownership rules