Only a small % of retail shorts will have to be covered on the small chance that GXY's price will bounce.
eg
UBS Australia borrows black rocks 5% of GXY
UBS Australia short sells the stock on-market into the waiting hands of a UBS Nominee account in Europe. Seperate identies so there is no ASIC flag.
Blackrock requests loaned shares back.
UBS Europe direct transfers shares purchased at a lower price back to UBS Australia (Dark Market) and there has been no or very little onmarket covering.
UBS Australia returns the shares to blackrock. They are not stupid.