They'll wind up using the same sort of protective techniques the superstitious used to use against witchcraft --- being careful not to shed any blood, skin, hair or nail clippings when engaged in their illicit activities.
I can see a scene in a science fiction movie (God forbid it really needs to happen) where the protagonist's best friend, despite the padded, blood-absorbing armor which they were when conducting sabotage against the state is injured, so that a single drop of blood drops to the ground --- while the protagonist looks on in horror and sadness. Then, the doomed buddy simply announces, "I've been blooded. Give me all the ammunition you can spare." and then goes off on a berserk, suicidal assault of the pursuing authorities.