It would be a gross violation of a person's inalienable rights. It's what NAZI Germany would have done if the technology was available at the time; instead, they used tattoos. Felons are humans and as such, they will continue to have some rights until they are no longer alive. With government over-reach, anyone could be legislated into a defacto felon. Just being born Jewish made a person a defacto felon in NAZI Germany. We have the Constitution that is supposed to help prevent government over-reach. But things that are legal today, could become felonious tomorrow with the stroke of a pen. The law is supposed to be a servant of the good and a punisher of the evil. And yet, at times, it has been just the opposite, even in America. Let's not be so naive as to confuse legal-versus-illegal, with right-versus-wrong.