This is both one of my pet peeves and a thing that legislators seem to love: Somebody does a thing that is already illegal, but in a slightly novel way. Perfectly valid statute exists to prosecute, but legislators want to be seen as doing something, so they pass another law to make the already criminal action more specifically criminal.
Arguably bans on cellphone use while driving are a good example. It's not that it isn't bad, it's that distracted driving already carries a hefty fine without being specific as to the mode of distraction. So does causing an accident, which presumably is the harm we're actually trying to avoid.
