Hang on we are over thinking this aren’t we? Apparently everyone knows who is at it. On which basis their aircraft have a registration, a transponder, home airfield, etc etc.
The problem is clearly evidence enough to prove that something is happening that goes beyond what is currently legal in terms of cost sharing. That is the issue and very sadly when you have an activity that in many cases people are prepared to pay 100% to do because they either enjoy it or think that with x number of hours it becomes something more. The prospect of paying something less than 100% is attractive, and currently you can pay 99.999999% less than a 100% and still be potentially legal and by the way nobody has defined what 100% is......