I hate to be the one who jumps on you here (leave it alone), but my high school experience *was* almost entirely devoid of adults. They were background--extras, if you'll stretch the metaphor. To some extent, you can make that argument about all film. The actors are central; anyone not involved is peripheral. Anyone over 18 and under 12 or so is peripheral to your average teenager. The rest of the world is practically imaginary; the entire perspective is microcosmic. (At least from what I remember/experienced with the older kids at summer camp.)

The "what if" premise needs a bit of work. The premise for Jaws is (by way of William Goldman) "what if the shark got territorial?" This changed *everything* about film (if you believe Goldman); but I'm not sure that makes Jaws a fantasy. There are fantastic elements, sure; but Spielberg's primary goal seemed to be terror, not numinous transportation.

Hrm. These terms need work. Either that, or I need to shut off my "exegetical fussiness." Grad school bit me hard.