In this case the warning is, there is a very high likelihood that they will send an artillery shell back in the direction the drone came from, pretty much guaranteed and then bluff it out with nukes. Do not play with other people's lives, it is seriously not nice. North Korea is run by psychopaths, totally out of control psychopaths versus our own somewhat constrained political and corporate psychopaths. Change will come only via the elimination of those psychopaths, want fast change, than just put your own life on the line, sneak across that border and well, make those psychopaths go away, good luck with that. Patience, attempting to communicate with North Koreans, not letting any North Korean leaders out of North Korea, ever for any reason, and cutting off all luxury exports to North Korea (psychopaths must have their ego driven luxuries) are the only way to go. Either North Koreans achieve their own freedom or they will just lose it again, much the same as the rest of us. Fortunately most of the rest of us do not need to resort to violence to achieve a social democracy instead of a psuedo democracy but actually a corporatocracy. For North Koreans the choice is either bite the bullet or eat the bullet.