Here's a fun and helpful website by Ted Pack that refers to this problem of unsourced "information":
He talks about a person in an online family tree who died before six of his children were begotten. The same man with the same dates and same children shows up in more than half-a-dozen other online trees (obviously the first mistake was simply copied into other people's trees without being reviewed). Let's do our homework people!!
That said, still there should be some Ancestry "leaves" showing records for somebody (perhaps the tree creater's parent, or grandparent, etc.). It seems improbable that anybody would create a family tree consisting only of mythical people.