David:
What is the source or reference for this statement?

"did you know that nearly 50% of glider landing fatalities happen during off-airport landings"

I've studied glider accidents for years and have not seen that - unless you are calling low level thermalling stall/spin ins, ridge terrain strikes, and similar accidents as "off airport landings"

Admittedly, a properly executed pattern,approach and landing into a soft field can cause glider damage - but a fatality? Those (in the hundreds of cases I have studied) are quite rare. What I have seen is that the real killer in our sport is low level thermalling - especially in wind/gusty conditions. But that's not a "landing accident".
ROY