Absolutely sure the cartels will be using these for hits, and also sure they will be adopted in smaller versions by governments and NGO's to to attack civilian dissidents. "slaughterbots" is a chilling vision of the future.
R/C aircraft were a pretty big thing back in the '70s when I was in college - a couple of other students raced them as a hobby. I asked one of them about using them to transport drugs across the border, and he said "We don't talk about that." He then continued to say that the radio control "handoff" from a controller on the south side of the border to someone on the north side was "tricky" and the payloads were relatively light.
I asked him about "kamikaze" R/C aircraft and - back then - a good video link for targeting was the main sticking point. But again, it was "We don't like to talk about that sort of thing."