Odee, they werent close enough to set the siren off. In CAP the local siren and base flashing range is set to 1 mile....more or less visual range. The reason for this is that in the early part of the war (as we are in now) radar and early warning systems weren't that brilliant.
As the campaign progresses and time moves on the early warning ranges will get longer. For example, in the next frame (Battle of Britain) dot radar has twice the range it did in the first two frames. This is to simulate the excellent, but still very new, radar system the British had set up.
Now as for last saturday, it's a COs option to time a raid of an enemy field to that of the respawn window. If I were CO that's exactly what I'd do, eliminate the enemy fighter threat before they get to altitude. However, I'd also plan for such an eventuality should I be on the receiving end. In fact......MAG-33 also spawned out of A12 when you got shot down, we grabbed west - away from the bad guys - until we had alt, then came back and shot down 3 109s and a couple of 110s.
