if non-technical means "avoid any techy words at all costs" then I suppose not. But unless one is totally brain-dead and likes to stick their hands in their ears and say "lalalala" at the mere utterance of anything that sounds like an explanation (and people like that, you just don't bother explaining anything to, they just aren't willing to learn), then I think it conveys the basic idea fairly well. You can always dumb things down so to a certain level but then the analogy only bares minor resemblance to the actual problem and teaches nothing. At that point you might as well say "SQL injections is baaad mkay?".