Folks,
Be very careful what you wish for, you might just get it.
Who was the great economist who said:"It is just as well we don't get all the government we pay for".
There have been some very ill-informed statements about the US and FAA, for a start, Class G airspace in US is very rare, transponders are not a universal requirement for VFR.
There have been some very uniformed statements about the use of various collision avoidance devices, but the ALL have one thing in common, they are not accurate enough in such as a circuit environment, or approach/departure areas to their airfields. And they are "head down" when you should be "head up".
I speak from considerable experience of such devices, pilots who are "gadget freaks" are also the one who already do not look out the window nearly enough, and put undeserved faith in their latest toy --- usually extolling the virtues straight from the manufacturer's sales blurbs, with no idea of the real limitation ---- and this is not a shot at PPLs, one of the worst offenders I know is a high time corporate pilot.
The first step is to properly analyze the real risk --- not the perceived risk.
The next step is, once the magnitude of the risk is established ( the ICAO separation assurance standard is a good benchmark), and there will ALWAYS be some risk, the next step is: What to do about it.
A good start is always to amp up the national on-going pilot education efforts. How to conduct a proper search, including making certain your eyes are not on a fixed focus, would be a start, it can't be emphasised too often.
When it comes to "mandating" equipment, sentiment ( I was going to call it loudly expressed ignorance) can cost a lot of money, the preferred process (about which the FAA is quite rigorous) is a cost/benefit analysis. using real costs, not fantasy figures dreamed up by proponents ( more properly called "proponent bias"). And I do mean cost/benefit, not cost/effectiveness --- which is a different thing. Most of you on this thread have been making claims about perceptions of cost/effectiveness --- not benefit.
Unless the cost (initial and ongoing) is less than the benefit ( using national standard cost for lives and damage) the idea fails. Whether you like it or not, life is not "priceless", a principle accepted throughout public planning processes, "the sky is NOT the limit" to save a life. This is the national statistical cost of life, not trying to put a value on the life of one individual.
I can say, with great confidence, that mandating ACAS/ ADS-B in Class G airspace in UK will not produce a positive benefit to cost ratio, based on work I have done over the years, indeed, it will not even go close.
At time like the aftermath of this recent occurrence, there is too great a tendency for kneejerk demands that "they do something".
Tootle Pip!!