In the good old days spinning was a mandatory part of the syllabus... and a way of saving time on descent from on high.
I am sure there were a few WW2 trainees who bailed out when Tigers or, later when Chipmunks were the go. Some old RAAF/RAF chappies might have examples.
When doing spins in sailplanes, again there would have been no problem seperating self from the machine... might have needed a good kick off, but do-able.
gx...The glider story is true... see back issue of Aust Gliding..."X" years ago. At Gawler was it?? Might have even made the old 'crash comic' / Safety Digest.
The US Stearman exponent, whose name escapes me, I think was the same guy killed in a mid air collision at an airshow.... he was flying the Stearman with a jet slung underneath. Spectacular exit that's for sure.!! You tube????
As for the Harvard guy... I'm sure he would have given it his best shot... how long does it take to jettison the canopy, punch the harness release... and heave himself over the side..5.?.10 seconds.???...MUCH better to try than NO alternative.