MACD indicator (and other major ones) are actually have a dead cross near 28/Sep 1987 and 7th Oct 1987, which warned everyone long there.
But Now, DOW just had its major indicators crossed lovely at the bottom,
this is Point One.
And
Before that, people actually did their business as usual, without any panic selling like previous 2 weeks in US.
I think only a lot of evidents(N>=30) can establish one point from statistical point of view.
Hope there are other more evidences to convince people :)