It’s more surprising that lawn darts weren’t banned until 1988 in the US, instead of the day after they first went on sale. And if you need a good reminder as to why you can no longer easily buy a set, Joerg Sprave built a lawn dart slingshot cannon that explains why.
Lawn Darts were a game from a simpler, more naive time. Sure, they could embed themselves in your little sister's head just as easily as the lawn, but they were fun. Now they're back.