Such action obviously could impact genealogists, not to mention law enforcement and others. I would guess it could also change the plots of all sorts of television programs.
There are two key phrases here: "without their consent" and "one law professor suggests." Most genealogists do obtain permission in advance before purchasing DNA tests on their relatives' DNA and a suggestion from one law professor is a long ways from becoming a law. Still, it is a proposal that bears watching.
You can read Michael's interesting article at http://blog.mocavo.com/2013/05/will-some-dna-testing-become-a-felon.