I once leaned the bonnet on my series 2 against the windscreen. The wind blew it back down and, whilst my head wasn't underneath, I did try to catch it ! Doh ! the pain as the bonnet slammed on my fingertips was excruciating !
Needless to say, I haven't propped a bonnet against the windscreen since
I've also had a 90 bonnet disappear over the top of my old 90 at 70 mph, an interesting experience but that's another story
Mo