Ahh yes, the dreaded UHMRA [Upper Heyford Mandatory Radio Area] the cause of much amusement for glider pilots. For some reason Uncle Sam wanted a big chunk of airspace to protect his F111s against GA. I don't know why this protection was needed, after all he had all the guns. Anyway radio contact was required to enter the area but once contact had been made you could do whatever you wanted, there was no 'control', more like a basic information service. Placing this UHMRA splat across the major north / south runs, and in the middle of a clutch of active glider airfields had the consequence that, on good days, the UHMRA controllers were completely swamped and reverted to 'continue own navigation'. So the only real effect was to pi$$ off non radio gliders, of which there were many in those days.
We had several US pilots at Bicester (RAFGSA) in those days and the bar talk was that Upper Heyford was used as babtism of fire training for controllers posted to European stations. You could listen on the radio as the convection started up and the cross country boys and girls set off. Initially all was calm professionalism but you could sense the tension as the rookie controller tried to give position reports to contacts about others very close (probably in the same thermal!) as more and more gliders popped up until the inevitable 'continue own navigation'.
Back to the original topic. Painting red bits on sailplanes has been shown by many studies to be pretty ineffective. The only colour which seems to work is black, and this would require a reformulation of the resins used in grp structures so it doesn't help the existing fleet.
I agree with other posters on this topic about the advantages of having an RT licence and many gliding clubs make getting one easier by organising group courses and tests on site. However in the near future I shall be forced (by mandate) to dispose of a serviceable 760 radio and replace it at my expense with one which will enable me to talk to gizzillions of people I don't want to. I shall also probably be forced (by exclusion from airspace) to fit at my expense a mode S. Since 99% of my flying is in VFR in class G airspace I think my safety would be better improved by retrofitting, at their expense, all power GA with bubble canopies to encourage pilots to look out the window.
Jim