You could swallow one and get away with it as long as there isn’t something ferrous inside you already. You could swallow two of them if you swallow them together because they will stick together and become one bigger magnet. Did you know that every Chromebook has one in the front bezel of the screen? I worked on Chromebooks quite a bit over several years and ended up with about a thousand of them. They are very small but if kids knew they were there it would be a huge problem. They are how the Chromebooks know the lid is shut. Our schools have as many as three Chromebooks for every student because they break down so easily and often that some kids go through several each year. Then they go obsolete after 5 years.
That all sounds about right. I worked in Radiology Informatics, and we had little lights that came with each high end microphones that the radiologists used that would light up when they had their record button pressed.
It was supposed to alert someone not to interrupt a radiologist dictating the result of some exam when the light was on, kind of like a studio light in a recording studio.
On the bottom of the lights was a very powerful magnet so you could attach the light securely to nearly anything that had even a little ferrous material in it.
We installed them, but people thought they were dumb and added to the wiring tangles, so we removed them. Before we threw them out, I pried all the magnets off the bottoms of them to keep, and they were pretty powerful.
I got my finger caught between two of them, and they gave me a blood blister!