Yes this is sort of what I was envisioning. Not as much one trusted librarian doing a favour, but a librarian team having a filing cabinet full of backup codes

Yes this is sort of what I was envisioning. Not as much one trusted librarian doing a favour, but a librarian team having a filing cabinet full of backup codes and an ID process that they trust and that is appropriate for their community. This is the sort of thing that I think Google could support explicitly with more access control around it, but I don't think that's entirely necessary to get the benefits.