See and avoid should be the last line of defence not the first.
I nearly found out in a big way not long ago. I saw the aircraft on the opposite direction track, I turned right as we are taught, the aircraft went past me on the same level and about 30 feet to my left.... my angle of bank at the time was just passing through approx. 10degrees. Had he been right in front... well you know.
Also how often as an IFR pilot entering a busy MBZ etc and BEING aware of the six other aircraft have you said 'where is he', even when you know they are only 2 miles ahead and 1000 feet removed.
Basic airmanship, CRM, CFIT etc. Every course you ever sit in aviation always mentions the fact that we should use every resource available to increase safety. We already have see and avoid and other resources, why take them away?
Heres a novel idea. The average private pilot cannot afford a safety pilot to do the seeing, so why dont they trade in their radios for a new HUD?