At my UK club parachutes have been used for all flights in club owned gliders for more than 20 years. Shortly after the then CFI made this a rule a ASK21 flying an introduction to gliding day was hit by an extraordinarily strong bolt of lightning and broke up. The instructor and student survived thanks to their chutes. Personally I had a midair collision with another glider 15 years ago. I and the other glider pilot both survived completely unhurt after using our chutes.