The premise of my question is that North Korea is as crazy, paranoid, and [over]reactive as a country can be. If there were UFO sightings, I think they'd be going crazy with nuclear threats, etc.

If this premise is correct, these are 2 of the scenarios I have been thinking about:

1 – If UFOs are man-made crafts, managed by human governments, then are we avoiding them on purpose?

2 – If UFOs are extra-terrestrial crafts, then are the aliens aware and careful not to upset Earth's geo-political status quo, despite sightings at military installations, including nuclear-capable ones?