""“They have to land for you to get the contraband off of them,” he said. “They can’t drop it like a bomb.”

This doesn't seem logical. I mean, (if) I were to attempt this, I'd fly a drone very high out of site of the guards, with a downward facing camera. Wait until I was over the correct area, and release the (heavy) tool that would fall mostly straight down. Seems pretty hard to spot / track / fail at. As far as dropping it, thats just a servo, hardly difficult.