"unless the shorter is the predator , which was the case for...

"unless the shorter is the predator , which was the case for tietto when it was shorted"

If a predator has borrowed and sold 84m shares in BGL as a way of lowering the SP before making a low-ball t/o bid, then the predator is taking the risk that somebody else will make a higher bid. If the predator gets outbid then the overall result would be a massive loss for them, because they would have to buy back the shorted shares at a far higher price than what they had sold them for. They would probably have to pay the higher t/o offer price, which might easily be 50% more than their average shorted price.

I'm not familiar with Tietto, so I don't know whether there might have been any competitive bidders. In BGL's case, the quality of the assets is too high for a low-baller to take the risk that nobody else would bid. If there was a low-ball bid for BGL, perhaps similar to what happened to TIE, then I think that other higher bidders would soon emerge if there appeared to be even the slightest possibility that the low-ball bid might be accepted.