Alright, reacting to getting shot at with cannons is one thing, but I notice that AI generals and units STILL psychically know when you tell your cannons to shoot at them. When the AI is performing its inevitable general suicide charge, one effective method I've found for keeping them out of the fray (initially, at least) is to target them with cannons. The AI instantly sends its generaly to the other side of the magic red line.
The AI also knows when you tell your crews to use grapeshot and will occasionally halt its troops just out of grapeshot range if you shift your cannons to that ammo before they meet your line.
The only effect this has on gameplay is to make the AI annoying and to make battles take longer. It was present in ETW, although to a greater degree, to the point where you could break the 'melee bug' by setting up a line of cannons set to grapeshot, the AI would refuse to come near them half the time.
Either way, it's annoying.





