?To be strong enough to clip you in and be able to pull on, it’d be a strong magnet and it’d probably be very difficult to unclip. Clipless, you can twist out – magnet, you’d have to overcome the strength of the magnet.
Not really, slide them past each other and the N-S poles would repel so releaseing would be easy.
I reckon it could be done with some sor of mechanical ‘switch’, like some doors, the door closes, magent comes close, and pulls the bolt accross. Dissengageing would be just like SPD’s, twist the foot and the magnet moves over another ‘switch’ which pushes the binding open. I like the idea of a switch on the bars too, but why not go further, automatic dissengagement when both hands arent on the bars, easy enough to measure resistance between the grips, as soon as one hand comes off, the pedals release.