Turns out the whole premise behind Be Kind Rewind isn't based in scientific fact! In the movie, Jack Black--with a brain magnetized by a civil disobedience act gone wrong--erases all the tapes in a Passaic, NJ video store, thus impelling the re-shooting of all the movies destroyed.

According to professional spoil-sport Jeremy Berlin, no way, Jose. He cites Jerzy Bodurka, a Polish physicist who works at the National Institute of Mental Health:

Overall, soft brain tissue has weak diamagnetic properties and cannot be magnetized to [that] level. If it could, then the kitchen, the mechanical shop, the hardware store, and many other places would be very dangerous environments for all human beings. So the answer to that question is NO.

In a few dozen years, or perhaps sooner, when nanotechnology, robotics, and power-generation technologies advance into something like a human-machine hybrid...such a hybrid [could] have a part of its body--say, an arm-equipped not with a deadly gun or flamethrower (like that cute-but-dangerous lady aka Terminator 3) but with a magnetic conduit.

That explains so much.