In his bailout lecture posted by the BGA, G Dale says that when he bailed out of his DG the impact of the headrest made him blackout briefly. That remark comes soon after 4:30 in the video.

https://youtu.be/cDXIxHAmSX0

Cheers,
...david

On Tuesday, September 17, 2019 at 9:04:54 PM UTC-4, Nick Gilbert wrote:
Dave - what you're saying may be true. Getting back to the original question, do you have anything to back it up other than your own gut feeling? Bearing in mind your original comments regarding the headrest being the cause of the fatality in question has nothing to do with bailing out.

Cheers,
Nick.