Yes, come to think about it we had an ASK 19 that our CFI could spin (he was about 50 pounds lighter than me) and I couldn't. I stand corrected, perhaps I should have said that I can't spin modern high performance gliders.........
DAR most accidents of this type aren't caused by showing off, they are caused by trying to grab a thermal while on downwind or finals to a field landing. I've seen people in competitions try and get away from about 200 feet...Either that or they try and stretch that final glide a bit too long with get-home-itis and fail to make it. Both bad airmanship of course (I'm not criticising anyone who has been killed or injured by the way, we've all had 'there but for the grace of God' moments) I suppose it's the old 'it can't happen to me' syndrome.