There was a big hoo-ha in Australia about 6mo ago where a 12 year old kid swallowed a bunch of them that were sitting on a high shelf in his father's locked study. So the kid, who is 12 and should have known better, went into his fathers office, climbed up the shelf, pulled down metal balls and proceeded to eat them. The mother went on to campaign for them to be pulled from Australian stores, which they were 4 months later.
Now the infuriating thing about this is that because of one *incredibly* stupid kid everybody doesn't get some awesome toys. My 26 year old brother in law is pretty annoyed because he spends a lot of his free time tinkering with big blocks of them and now he can't get anymore. These are not children's toys and it is foolish to ban them entirely because some dumbass kid was stupid. By that logic you'd have to ban every adult product on the logic that it was not safe for children