Presumably when using a RIS I need to provide the controller with a bit of help...things like height, heading and routing? Well my height is going to between the ground and the base of any controlled airspace. I could go from one extreme to the other in four minutes (1000fpm isn't unknown in UK). My heading ? I rarely maintain a heading for more than ten seconds. My routing ? If I only I knew! Flying from, say, Wycombe to Enstone may take me down past Abingdon, routing alongside the edge of the Brize Zone, West of Kidlington, up around Weston-On-The-Green OR East along the Chiltern Ridge, up to Aylesbury, across to Milton Keynes, up past Northampton, then West and South of Hinton-In-The-Hedges. Either route depnds upon the conditinos experienced during the flight (and necessitates avoiding several parachute sites in the process). Oh, and while I'm doing this flight there may be 10-15 other gliders all attempting the same thing. Not sure how happy ATC would be to have 15 different gliders all reporting that they're operating in the Oxfordshire/Buckinghamshire/Northamptonshire area between ground level and 6000' . That's all from one Club on a not particularly busy day. Combine that with activity from (say) te other Clubs and you're never going to get through on any RIS/LARS frequency!