Is it a rules violation for a pilot to intentionally frighten a passenger to the point of hysterics? I saw a "viral video" inside what looks like an inline two-seater being flown from the front seat (shot from the back seat). In the video the pilot slumps over sideways against the window and throttles down, increasingly letting the nose dip, while his passenger freaks out behind him thinking he's passed out and they're going to crash. Eventually the pilot throttles back up and levels off, then turns and smiles at his passenger, having played a trick on him.

The video is almost certainly staged (given how steadily the supposedly-hysterical passenger holds the phone taking the video), but it made me think: Given the unpredictability of people when faced with a life-threatening situation, if it were real, would the pilot in question be breaking a rule and/or law by inciting hysteria in that way? (As opposed to just acting like a massive [expletive deleted].)

Dave, whose eyes are clearly better than mine, says the plane is at about 2,900ft when the pilot starts his little trick and 2,400ft by the end of it, briefly exceeding 1000fpm descent. In addition to my main question, I'm curious whether that's a factor in whether it was a violation; goofing around at low(ish) altitude seems like a Bad Idea™. But the altitude is a side thing (particularly as they were clearly much higher than I originally thought), I'm primarily interested in intentionally inducing hysteria in a passenger.

I suppose we have to choose a locale, so let's say in the U.S.
There's no regulation that I can see that says "don't frighten your passengers". And there probably shouldn't be: almost anything could frighten a nervous person who isn't familiar with aircraft, even if the maneuver (or whatever) is completely normal.

Having said that, if the FAA thinks you've done something stupid then they do have a 'catch-all' regulation that they could argue you violated.

14 CFR 91.13


  No person may operate an aircraft in a careless or reckless manner so
  as to endanger the life or property of another


I haven't watched the video but I think it's at least plausible that the FAA could say that there was a real risk that the panicked passenger would take the controls and try to fly the aircraft themselves. In a dive, pulling up suddenly could easily stall the aircraft and stall recovery is not intuitive or obvious to a non-pilot. In the worst case, pulling up suddenly from a dive can actually tear the wings off. So it would be very easy for the passenger to damage or destroy the aircraft and potentially fly into people or property on the ground. 

Finally, apart from the aviation regulations, it might be possible for the passenger to sue the pilot for causing stress and emotional damage. You could always ask on law.SE about that.