Traders are just like programmers, in that they often wish there was a 'Do What I Mean' instruction.

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.

If you don't do it, the traders get mad when they make a mistake and it is dutifully executed.

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.

That said, I'm sure this sort of error has cost banks far more than a single $150k fine. The losses on a bad trade can easily outstrip that wrist-slap.