They do. You'll be hard pressed to find a magnet room without this [0] sign on the door. That said, it's probably not that warning to most people. Fridge magnets are always on too.
Yeah, saying ‘serious injury may occur’ is the same as saying serious injury may occur when doing sports. It’s too abstract. I need an image of my keys being ripped out of my pocket and being stuck to the machine to really understand what will happen.
0 - https://www.zzmedical.com/exclusives/mri-warning-wall-sign-m...