If they are dropped they are as safe as any other shell or round of loaded ammunition. If the primer is hit just right, yes, it can discharge. However, that possibility is more than extremely remote.
In competitions when we have to "unload and show clear", the common method is to simply cycle the action and let the loaded round that was in the chamber fall to the ground. No one gives it a second thought.
(with a little practice though you can catch the round in the air
)