Bookworm,
My point exactly. We as humans are not very good at it, so we should spend proportionately more time doing it. I, like TonyR, have experienced pilots to whom looking out is secondary to other less important tasks.
Alphalpha,
As has already been pointed out on this thread (I assume by ATCOs) radars are not reliable for picking up light aircraft. If everyone in that area was receiving a RIS, there would be bedlam. No one would be able to get a word in edgeways.
As for Mode S. Yes it would be a good idea, but the affordable GA versions of TCAS (as far as I know) do not give an azimuth for contacts. It would be worse than a RIS. Also will microlights be required to carry a mode s Transponder?