Pretty Little Process of Elimination: Who Isn't "A"?

OK, granted, a few of the parents have done some shady stuff. Some have even done things that scream "A." But I just can't entertain a theory in which one of them would want to hurt someone else's daughter, including their own. Not to mention, they have too much adult stuff to worry about. Plus, are they even tech-savvy enough to pull something like this off?