According to regulations, what should a mini-drone do once it is out of the control range? Would it continue flying even if it receives no signal?
What about full size drones?
Let's take it from the top: it depends on the drone
Regular, off the shelf hobby drones, might just turn off and then fall to their doom. Some more expensive ones, might have a feature to safely land (instead of dropping like a rock).
Considering military ones, it all depends on the programming and the manufacturer. Some drones have parachutes, so that could aid them when they run out of juice.