HWD
I never said everybody should have TCAS. It's 15 grand or so, min, for the cheapest systems that give azimuth (essential).
I didn't even say everybody should have a Mode C transponder (I do actually think that).
What I have been saying is that the benefit of a lookout is illusory [hears the sound of windows at CAA Gatwick and Kingsway opening and the entire GA Dept jumping out] and that
if one is after a solution it has to be TCAS, and obviously that will never work properly until Mode C is mandatory.
Luckily for most, midairs are very rare so, for the typical GA "low value payload" (you or your granny) there is very little reason for spending the money.
And even if you do spend the money, it won't pick up maybe 50% of traffic because they don't have transponders or have them switched off, intentionally or not.
Those commercial pilots here swearing blindly how wonderful TCAS is must be aware that they are missing a lot of stuff
I would bet that below say 2000ft > 50% don't transpond, especially self fly hire pilots. Higher up it will be a lot better. Most owner-pilots that go distances switch on Mode C religilously.
I wonder what will happen in 2009. What will they do about e.g. gliders and vintage planes with no electrics?
It doesn't bother me; everything in life is a risk and the sky is big and is 3D. I just don't like to bet against known odds, like joining overhead with 5 others, of which I can see just 2