I thought it was the AEF for which ATC (radar?) was deemed necessary. If so, I cannot say that I am surprised. When Old Sarum was an RAF Station with a large grass airfield with no marked out runways, we used to operate ATC gliding and light aircraft together quite happily. In fact, several of us did our PPL training when ATC gliding was taking place with no problems and no air traffic control.
Then, during an Easter course, in moves the AEF with their Chipmunks and and their own air traffic controller. Gliding had to stop whenever there was a Chipmunk movement within 5 miles. The gliding instructors and cadets were getting very frustrated as the launch rate was so poor that any serious training that week was looking impossible. The poor controller tried to be flexible and let one Chipmunk take off with a T31 well established on the winch launch. If the AEF pilot had done what most of us were trained to do, keeping straight until 400', I am sure that there would have been no problem. However, for some reason, the Chipmunk pilot carried out a hard left turn much lower than this and flew straight into the launch cable. Fortunately, the cadet in the back seat was completely unhurt. The glider was unaffected.
Depending on the airfield, all it needs is some local rules to which all parties sign.