You're missing my point. The "good people" would sign UP with them to keep an eye on them and stop them from within if needed. Why I mentioned a "frag".
It's hard to be a stormtrooper when you have to watch your back among your own forces.
Hence, I don't think that will ever come to pass.
Every "stormtrooper" in history has had to watch his back. Whether it was the SA, SS, Khymer Rouge, NKVD, KGB, Stasi, Securitatia, etc, every member has known that a subordinate trying to gain power or a superior in a moment of pique could be (and often was the end of them).
Fear of the public or of internal dissent has never eliminated an oppressive force; it's only strengthened. The answer to "good people protecting the innocent" is making sure said good people are on the front lines oppressing the innocent. Once they've ground their jack boots into a face or two, they become what they hate in their own eyes or the eyes of the people. It's hard to say "I'm on your side" to a person whose father or mother you helped eliminate.