Hidden items don’t help the site. It takes up DB space, and only adds to the burden of moderating them.
I’ll remove the hidden upload option and offer the “Private Vault” instead.
Users can mess with it any way they want to. Recreate the last days of Pompeii—or whatever—in your Private Vault.
Also, I’ll offer an encrypted back-up method so that users won’t lose their private vault in case of device reset.
Since it’s encrypted with a PIN, admin won’t be able to open any user back-ups.