Axiom,
I was not apportioning blame on the glider pilot...my memory of it is as you say, they took off and climbed into the Blanik's flight path...merely using it as an example of the limitations of see and avoid. Bill was a mighty fine chap and so was Paul Hardy. Both very experienced and consumate professionals. Be that as it may, as the story was recounted to me the impact was around the ruddervators and they then lost control.
Chuck.