This issue has caused me considerable angst during the design process for the car, we went thru several options and ended up with the Aero clips like Bills, we have 4 on the rear clip (The pin can engage either from underneath or from the side). It makes the lock down mechanism a bit tricky but assuming you remember to do it, it should help hold things together in the event of a shunt. We have also really increased the security of the hinge plates , front & rear. If you zoom in on the attached photo you can see the side mounted catch.
I, like many others I imagine, have tried to develop a pre race check list to tick off in the marshalling area, and I like many others sit there strapped in tring to remember if you have remembered everything on the list !
I like Ross's idea of reaching round the door to check if the locking mechanism is in place
Iain