While all of this is true, I think it's only natural for beginners to ask such questions, and they need to get satisfactory answers if they're going to invest the time the long road takes. Dismiss the question out of hand, and you may have just lost a student.
The answer to any of these questions is the same: "Oh, I'd just have the circus ponies trample him to death." And when they ask, "Wait, where did you get circus ponies?" you answer, "The same place you got a 6' 5" heavily armed deranged Navy SEAL who wants to kill me (for reasons unexplained), and who was able to approach me without my realizing it until he was six inches away." Or, you know, fill in whatever improbable scenario they're talking about. In this scenario, I suppose it would be, "a very strong guy who has a very strong grip and an invisible force field around himself that allows him to grab onto someone else and simply stand there without anything happening to him." Ultimately, any of these "does it REALLY work" questions can be answered with the circus ponies: if the questioner has the right to set up an absurd proposition as the premise for the question, why should the respondent not have the same leeway?