I had the bottom equivalent pop off after a stupid takeoff attempt from a platform that was not _quite_ large enough. Ground effect caused a tumble. Well, really pilot error caused it, but I'm sticking to the physics. I did not know it was missing until I went out again to fly from the same place (from the ground, this time). Did my preflight and discovered innards exposed not anticipated. No flight today....until I saw next to my foot a piece of gray plastic. It popped right back in and flight has resumed.
I don't trust that piece of plastic, but I trust the rest of them, so will continue to launch.