Depends...
I don't think they will ever have to cover.
If they are short or "short" (ie. FTD). If there are FTD's in this stock, then revocation will not let them off the hook. The burden of proof falls on Frizzy, but he's on a mission now, so I'd place my bet on him to expose the NSS in this stock.
But at this point, they stand a chance of covering a lot of FTD's since the company has dropped the ball at every possible opportunity...there's a chance that any NSS Frizzy proves down the road, will be quite small.