I'm speaking from experience. My son bought a very small (thumb-sized) but very powerful magnet when he was in junior school, so maybe 15 years ago. It must have come from one of those gadget shops that were popular on the high street at the time. He ruined an old CRT TV screen with it, and certainly, a watch would not have survived contact. I think there are still some metal objects around the house magnetised by it. We took it away from him and hid it. That video does have several bold warnings shown, but the idea that these are toys or fun gifts, and that science experiments should be conducted in the house rather than a laboratory is quite wrong.