Traders are just like programmers, in that they often wish there was a 'Do What I Mean' instruction.<p>If you look for duplicated orders and request confirmation, the traders get mad that there are extra clicks keeping them from doing what they asked.<p>If you don't do it, the traders get mad when they make a mistake and it is dutifully executed.<p>If you do it only over a certain threshold, the traders get mad when they make a mistake that is large, but not over the threshold.<p>That said, I'm sure this sort of error has cost banks <i>far</i> more than a single $150k fine.  The losses on a bad trade can easily outstrip that wrist-slap.