If they were hostile—clearly they're not intending to be secret, since they have bright lights. So if they're not trying to spy, what else might they be doing?

If they were hostile—clearly they're not intending to be secret, since they have bright lights. So if they're not trying to spy, what else might they be doing? The most likely explanation I can think of is, they're trying to provoke a reaction, to see what defenses the US has against hostile drones. So you can take that information and build defenses for your drone. So maybe shooting them down isn't the best idea, unless they begin to pose a more direct threat.