Bookworm,
I think you missed my point? I'm not saying see and avoid is going to save you every time, I'm simply saying that fancy gizmos won't either! Take your example ... do you think that a buzzer telling you a bullet is incoming at 2000 mph is going to help you dodge it? lol
what I am saying is that good lookout and situational awareness are the best defence you have overall. Situational awareness does of course include being aware of other aircraft in the vicinity or likely causes of conflict picked up from your chart either before or during your flight. The dot to impact can be less likely if you know where to look, and that's where radio ect can of course help, but in the end eyeball and brain is the number one defender against a collision in a typical GA senario ... It's quite a seperate issue for IFR traffic.
SS