well, case in point. Just as I wrote the above, the following happened on the nqs (look at a chart for 8/8/01 starting at 13:45)
In five minutes it went from 1685 to 1670, and then BAM, it fell all the way to 1650. Now this last one may be a bad print, but I was setting here watching it and it happened. Then, instant rebound back to 1670, four minutes of piddling around, and then a knife in 90 seconds of going 1675 to 1665, four minutes after that and we just touched 1660. If your swinging size when this happens, it could hurt, and you may find trouble when your stop gets hit and there is not a lot of liquidity AT THAT POINT. Hence, the 20 point drop.
Best,
Mike