This is a much exaggerated concern. While it is theoretically possible for a 1911 type firearm without a firing pin block to fire when dropped, it is very unlikely.
The firing pin is held away from the primer by the firing pin spring, and the momentum of the firing pin must be great enough to overcome the spring and hit the primer hard enough to ignite it. To do that, the piece has to be dropped from a considerable height and land on a hard surface with the barrel pointed straight down. If it did fire under such unlikely circumstances, the bullet would by definition hit the hard surface directly.
If you stood on the roof of your house and dropped your pistol onto the concrete driveway enough times, you might eventually get it to fire straight into the concrete. But you would have to work at it for a while.
Note that it is firing pin momentum that would cause the piece to fire. Whether or not the hammer is cocked has nothing to do with it.
When parachuting, if you land hard enough to make the pistol fire, you probably will not survive the PLF. I never did get a definitive answer as to whether the forces of an ejection seat could fire it, but suggest keeping the chamber empty when riding in a aircraft so equiped.
Otherwise, forget about it.