Also, while I'm a native speaker who does know this one I think it's obscure enough that most don't. In fact I suspect it's obscure enough that the mis-spelling will replace it eventually anyway.

Incidentally the products of magnet fishing often turn up on Reddit's /r/whatisthisthing sub. You also see quite a few munitions. Often enough, in fact, that they have a munitions bot that warns people to contact the authorities (and not, e.g., twist the end to see if it comes off...)