Bounty Hunters that break the law attempting to recover their contract assets at the wrong address are legally liable for the damages and if they get ventilated, perforated, and punctuated by a person in the wrong house then they pay dearly for their mistake.
If their lawful prey is there, they pretty much can do just about anything. If they make a mistake and their lawful prey isn't there, they can go to jail for a long long time if they survive.
But if you shoot one defending a perp, then you are going down hard. In otherwords, if you have a bail jumper in your house, you better be willing to give him up because they can use whatever force is necessary to take him into custody and they can protect themselves. In other words none of the normal defenses are available to you that are otherwise available when protecting innocent people.