On Wednesday, November 6, 2019 at 6:12:51 AM UTC-8, wrote:
Maybe the tether doesn't work because of unexpected sink or a deyhdrated pilot, but when it fails I'm at least on the way to the safety point having started with enough energy to get there in theory.



I don't believe in "unexpected sink". Sink always finds me, and it finds everyone eventually. Flying over rocks with a landing site at max L/D away (even with your safety margin set to 800 or 1000) will eventually land you in those rocks, at least out west. This is what I was talking about in leaving enough margin for error.