No, never had that issue. I even just open my AirPods case, turned it upside down and shook, and was unable to get either of the AirPods to fall out. Instead, what happened sometimes (if I shook the case "forward") is that the case would close and not reopen.
The AirPods case uses some relatively strong magnets (for the weight of the AirPods) on the lid and to keep the AirPods in the case. If someone has an issue with them falling out, I suspect either a manufacturing defect or they've "done something" to damage them. And, don't forget, if they do fall out you can use the Find iPhone app to help you find your AirPods -- with the noise they make, the AirPods should be fairly easy to find if they just dropped off a nightstand.