Outside of gliding competitions, there were also plenty of people flying above 3000 feet on other tasks, whether self-selected or club gliding tasks. I flew from Essex to Saltby, Lincolnshire, and back to Ely, much of the time above 3000 feet. I encountered several other gliders at similar heights, nothing to do with the main competitions.
The previous week, when flying between Cambridge and Suffolk in the Lakenheath area, I heard the pilot of a transponder-equipped aircraft near Bury St Edmunds making repeated efforts for his squawk to be seen, and Lakenheath could see nothing of him, on either primary or secondary radar. So please don’t think that having a transponder automatically makes you visible to air traffic control. Like any other machine, they are not 100% reliable.
Regarding wider use of FLARM, my personal opinion is that for the UK, use by gliders will increase slowly from a few per cent to a significant proportion, when the critical mass will be perceived as being large enough to encourage most glider pilots to use it. Unless something better comes along for powered GA, I think it quite possible that the same thing would happen, with the timing a few years later. [Always provided that it is permitted, and not prohibited, by the CAA or other authorities.] I suspect that the middle phase, rapid increase in use once a critical mass is reached, will happen because those without will be shown how many more aircraft they can’t see that are in fact detectable. Just my opinion.
Chris N.