I thought vectorable thrust could run you afoul of ITAR, and pushed you into a much higher realm of scrutiny, since you've basically designed a missile.
In the article he declares he is doing stability control as opposed to guidance control, and only the latter is regulated.
How do you land without doing guidance control?
He's not landing it back at the pad or anything like that, just wherever it happens to be coming down at. Then keep it vertical(ish), keep it from moving too fast sideways or it'll tip over (again, stability, not guidance), and wherever it touches down, it touches down.
So by design, the rocket motor is going to be active, and pointing at something he doesn't control?