I doubt users will lose the stocks. This will be really weird. Worst case, you will be given some time to transfer your stocks to another brokerage and perhaps RH will make that process a lot faster than the nominal 2-3 days it takes now.
In practice, share lending is backed by (over)colateralization ( e.g cash or highly liquid short term debt).
The worst case for you would be to receive cash instead of the he stock itself.though this doesn't give relief to the broker not to fulfill its obligations.
