This is a nonsense suit. The first time we bought a box of these, one of the first things we noticed was the warning about the dangers of strong magnets and the risks of swallowing them in particular.
So adults fail to keep the product say from children, despite the clear warnings (which have already been upgraded by the distributor in response to a previous warning from the CPSC), but the CPSC thinks that amounts to a product defect. Also (pp 41-44) the magnets are too attractive and interesting to children, for whom it is 'developmentally appropriate' (p 17) to stick things in their mouth below the age of 14 or to make fake piercings as adolescents.
What. The. Fuck. On this basis we can go on to outlaw nails, screws, buts, bolts, and coins. We have about 15 sets of these things and don't want our money back. We're well aware of the hazard and don't allow children to play with them.
It's interesting, and important, that you read right over the part of the complaint where it is explained that tiny high-powered magnets are qualitiatively different and more dangerous than the other metal objects that children might typically ingest.
Why? Because the completely nonintuitive nature of the danger is itself part of the danger. People think these things are less harmful than, say, tiny screws. After all, they're smooth and round and clean-looking. They'll just pass right through, yes? It's not as if humans have metal parts inside for things to stick to, right? You didn't realize the danger. I, until ten minutes ago, didn't realize the danger.
But the danger is there. From paragraph 18:
If two or more of the magnets are ingested [at slightly different times - ed] and the magnetic forces of the magnets pull them together, the magnets can pinch or trap the intestinal walls or other digestive tissue between them, resulting in acute and long-term health consequences. Magnets that attract through the walls of the intestines result in progressive tissue injury, beginning with local inflammation and ulceration, progressing to tissue death, then perforation or fistula formation. Such condition can lead to infection, sepsis, and death.
I love my buckyballs and I wish I didn't find this argument compelling. But I do. I've dissected intestines (in mice); they have very thin membranes. I've had too many magnets pinch me. I've tried to separate buckyballs on purpose with my fingers; they don't separate by accident. If they capture a piece of tissue between them they aren't coming apart until the tissue dies and a hole forms. If that hole spans your intestinal wall you have a very big problem.
Meanwhile, this is apparently not just speculation. There are data. This has actually happened. Presumably it can be made to happen again in laboratory rats if necessary, though I frankly doubt this complaint will get to that point.
This is why I don't put them in my mouth or nose or ear, or let children play with them. Now, while this particular mode of operation is unique to magnets, do you really think that sharp screws or small nails are going to be kind to your intestine?
It is possible that even when compared with nails, magnets are uniquely dangerous.
It was actually mentioned in the Reuters story that one 4yo thought the BuckyBalls looked like chocolates. (http://www.reuters.com/article/2012/07/25/us-usa-buckyballs-...)