well there ARE bindingless bindings (?)
there are clip on bindings.
so, there are "bindings" that are not the traditional snap on bindings. but most people don't use them, and i'm not sure exactly the way you get out of bindings.
i've actually thought about this a lot. i like to think about how much would real world situations, whether it be physics, technology, etc., that would ACTUALLY limit SSX.
i don't know shit about physics, so totally correct me if i'm wrong, but the only way to make magnetic boards work is if there was a way to cancel out the magnetism, or as Ranz has been saying, repel it instead of attract. and even then, there would have to be a way to neutralize the magnetism so that while you're flipping, kickflipping, spinning your board around, your feet don't just randomly stick back on the board mid air.
but, as far as i know, i'm not sure you can just neutralize a magnet like that. if there is, i'm sure it's a very expensive process (which is i guess why the boards in game are thousands or millions of dollars). but to me, that would be the only way it could work.
the rider holds a switch or has something connected to them that they can press, which then initiates the neutralization of the magnets on the board making them not magnetic, do your crazy uber trick, put the board generally where you want it to be, press the button again to get the magnets working again, you're attached, land. seems relatively simple.
another problem i think there would be is the intensity of the magnets. you'd want them to be powerful because you don't want it fall off going down a huge cliff face or sketchy run, so you'd want it pretty much permanently attached as you're going down the mountain. my point is that using a magnet similar to how a fridge magnet works would be a bad idea because even though it may make the tricking process easier, you could very well lose yourself just simply going down the mountain.
i have some ideas for other kinds of bindings that wouldn't require a magnet but... maybe that's for another time.
and yeah, i've thought a lot about this. haha.