Sorry for bumping but just came across this topic and seems an interesting feature that no other sim is properly simulating.
So, my 2 cents on the difficulties commented by the ED team:
I partly agree as this hasn't been done before in other sims, but personally I cannot see a big deal on programming this:
No, they can see you (VID).
Just think the same way they would do in real life. In this case they shoudn't shoot as they are expected to be there (ATO).
My opinion on this is that you could either simulate ATO knowledge and "contact history memory" or you could take a simpler to implement solution using "god mode SA" such as checking "god mode" picture and assume the former situation if friendlies are within lets say 50nm.
I would say vis ID as long as friendly units are supposed to be operating in the area at that time, target is not maneuvering against us, RWR/ELINT is naked, no NCTR info, and AWACs/GCI/CIC/any-other-form-of-CCC don't declare the contacts as hostile...
It would be great to have this feature in DCSW as it is something indispensable in todays electronic battlefield, and no other sim has been capable of properly simulating it to date.
Harpoon 3 and Dangerous Waters are the only military sims with something similar to that.