Lots of good ideas here so I may as well plug mine. There are more than 80 of these out in Sonexland and I have not heard of one failing. They lock in two ways:
1. The handle goes over center.
2. The handle is locked in place by a ball into a recess in the housing. It can only be released by pressing a button on the outer handle or pulling the release knob on the inner handle.
It's also pretty intuitive to operate. For more information check
http://www.ansoneng.com/sample-page/products-summary/canopy-safety-latch/It won't prevent your alignment pin from falling out but my canopy is a pretty neat fit. I think that once the canopy is closed it wouldn't be possible for it to move enough for the hook angle to slip out of the holes.
Peter