[tristanc]

Just a note for those of you who may be in a similar situation. YMMV.

If you have a couple of very large folders (even 1 TB or more) you care about holding onto from your unlimited drive, share it with a few (even throwaway) personal Gmail accounts. Once my HS disabled access to my account after I graduated, the school admin account somehow inherited these folders (the organization name is the new owner).

I still have access to these many TB large folders many years on in the “Shared with me” section of gdrive.

[orware]

Check out my comment above here in this same thread which basically confirms exactly what you just shared here...this is the same tactic I was observing being used with fake student accounts sharing with outside external Gmail addresses which then appeared to take over the Shared Drives being created in GSuite, allowing for TBs and TBs to be added in to the drives by outside users. It seems like a big problem to me...but at the moment I don't think Google is providing good enough tools for Admins to see/eliminate these situations very quickly/easily.