You have to watch the L2 activity per trade each day, with volume (trade sizes) and know some fairly detailed history. That and some other indicators work together to know it's shorting.
I guess the shorts won... even though there was never really any that would have made any difference at all ... wow the good ole days where CDIV was .72 and people were telling people to slap the asks cause da float was locked... lolzzz ;-)