A fair remark, Paul, still I'll stand my ground: for announcing where I am, I will use something decent. This is after all both towards ground stations (my main concern) and towards other pilots (a side benefit). On the receiving side, I might be less demanding, as I consider electronics only a help in detecting other traffic. Not wanting to redo the discussion on the Mk1 eyeball, though, that has been done to death.
As for gliders using Flarm: it must be quite general yes, on the continent too. Still we should not follow them in this abhorrence. At my homefield, the better equipped gliders carry both Flarm and ADS-B transmitters - if that isn't a waste of payload and of electric power!