If you see a lot of BUY and Borrowed stock returned, they are covering. If you see lots of recent borrowed stock, they are shorting. Frequency of transactions isn't the key. It's the volume of the transactions that determines their position and they are clearly closing short positions in an orderly fashion by buying new stock and returning stock they already own. So in essence, they will not burn because they already have offsetting long positions to cover any shorts they still have outstanding.