When playing against the AI (PBEMs are different) I do much the same thing.  One of my house rules for playing against the AI is:  A unit must have at least a tentative contact to Area Target.  If it does not have the tentative contact it can’t react (because as far as it knows there is nothing there).  This encourages me to use the C2 system and information sharing.  I think it is pretty cool to send an infantry team over to a tank to horizontally share contact information and then allow the ta