I think it's safe to assume that some banks do keep scans. It's been ages since I opened an account, but I'm pretty sure they made photocopies of my ID.
All banks do that.
Have oppened accounts 3 weeks ago and you better believe they kept everything...
IDs, invoices, proofs of housing...
I just showed an ID about a year ago when opening an account and they didn't copy it as far as I can remember. Actually I have opened 2 in the last couple of years and didn't do anything but show my ID.
I dunno, maybe they copied my license I seriously can't remember but I do know that is all I provided.