The possibility of "Unintended Consequences" is often used as an argument against instituting a government policy or taking various actions in the private arena. And certainly it's something to consider as sometimes the unintended consequences are truly terrible (though in this particular example, the terrible consequences, while clearly unintended, could have been foreseen).
But I think the unintended consequence argument is used far too often. If we all refused to take any action because of potential unintended consequences, it would paralyze society. I could use unintended consequences to argue that I should never leave the house. It could be that when I open the door to leave I spook a mouse and that causes a cat to jump which causes a bird to flutter upwards and land on the tree branch above my door which, due to the extra weight of the bird, breaks off of the tree and falls on my head and kills me instantly. Or something like that.
The resulting paralysis of society from using the unintended consequences argument too often would be an unintended consequence of deploying the unintended consequences argument. That also could have been foreseen.