FMAA and CMAA.

[caravel]

The thing to remember when ambushing from the woods - that is emerging from the woods in a charge to surprise and enemy - is that you should click to select the ambushing unit and then once on the enemy unit, any subsequent clicks will negate the surprise attack penalty that is inflicted on the target.

So for example if you had your Ghazis in the woods on engage at will and in wedge formation, you would click once on the target and do nothing more. I believe that double click to run also negates the effect as it counts as a second attack order. The way to have the unit run is to do CTRL+R after you have ordered it to attack. I have massacred pinned units of Kataphraktoi from the rear using Ghazis in this fashion.