Except you could fly underneath radar in actual life. Or in the clutter, most of all during WW-ll. In actual life there is no base flashing when a low level raid is coming in, and the occasional blip of some noob who keeps breaking dar is often written off as a flock of birds or some other such thing. So if its realism you want then every thing except the radar should be turned off.
Oh, and in real life you cant switch countries or shoot your buddy a message that an NOE raid is coming from the country he's currently on.
Frankly I join these raids, or dive bomb, after spending fruitless nights looking for good 1 on 1s that are actually played out to the end. Most of the time its one HO'ing gangbang furball after another, "accompanied by babbling insulting morons on 200". Or pickers in run-90s and runstangs coming in from 30,000' that run every time they screw up the pick. Even the DA aint much better.
During the BOB the Germans made some very succesful low level raids against Brit airfields using the Do-17 completly evading radar. Had they kept this up the Brits would have been in big trouble, but instead they stupidly changed tactics and started targeting Brit cities and industry.
Flying under dar is much easier in AH probably because "flying" is much easier. And if you hit the ground then who cares? It wasnt done so much in real life cause it was a lot harder to fly heavy bombers so low in actual 3D space. If one bomber had a technical problem, which almost always happened, then he would have to grab air to make it back home and probably blow dar.
But the biggest reason NOE attacks went out of fashion is that it just became pointless to expose bombers to low level ack and obstacles as anti-radar tactics and technology evolved. The use of window and jamming devices gave the Brits a great egde in night raids by '44 and by then we Yanks had Mustangs and Jugs going in with the 17s during the day. We used anti-radar devices too but the Brits were the real masters of Dar in WW-ll. Even today, when were not using our stealth aircraft, conventional warplanes go in high accompanied by radar jamming and wild weasel escorts. That is if the enemy radar net even survived our opening nights strikes, which is doubtful.
So for a computer combat sim its pretty well balanced. In actual war radar, radar factories...ect were, and are, very high value targets. And if anything the game is geared towards giving an edge to the defenders, what with the base blinking for 5 mins even if radar is down. The base even keeps blinking if the attack is defeated and the goon is still within the dar ring.