Robert John wrote:

Never assume the glider is stronger than the placarded
limits.

Don't get me wrong: I didn't say because there's a safety cushion of 50%
you should go for it. Don't! I said theres a safety cushion of *only* 50%
to catch the unpredictable. Besides, as you pointed out, the placarded
load limits are for "straight" load only. Add some twisting forces, and bang!

Stefan