A&C,
I agree with your view, but the RIA makes it very clear that they don't wish to consider exemptions for other than a small subset of aircraft (hang gliders, specifically).
There are now many thousands of cheap and simple microlights and foot launched powered aircraft flying in the UK (the total number of microlights and foot launched powered aircraft flying in the UK is between 6000 and 8000). There are likely to be many more when the deregulation of single seat microlights gets into the ANO in the very near future (within the next 12 months, in all probability). For these aircraft to carry a transponder of any description is going to be a very real challenge, on cost, power consumption and radiological safety grounds.
My beef is with the broad-brush mandating of Mode S to ALL powered aircraft, irrespective of cost, safety or normal airspace usage, not the wisdom of fitting it for those who have the money to spare. To be completely honest, if I had the cash and an aircraft with an electrical system I would seriously consider fitting one, but there are many more pressing things I need to buy to keep myself and my aircraft safe.
What needs to be fought against, in my view, is the mandatory fitment to all powered aircraft and gliders, not the very existence of the system.
VP