Obviously the killer is going to become aware of you ~ you could be an aggrieved child, an angry brother, a widowed wife, and there you have the puke who killed your son, wife, brother, father or whatever, and he'll be on the lookout. In fact, he'll probably have already gotten a prohibitory order on you.
So, how do you get close enough to this guy to exact revenge, or re-balance the scales of justice, or retrieve honor?
Well, you don't have many choices there do you once the government has decided to protect the killer.
I would say you have been FORCED to use a hired killer from somewhere else ~ simply because he's probably not only more experienced, he'll probably be able to get much closer to your target than you are.
FORCE is the correct word.
NOTHING should be prohibited from being subject to a lawsuit in court. That simply puts us back a couple of notches into a state of nature and at that point hunting rules prevail. Bringing in a sharpshooter from out of town is always acceptable under those rules.
I say we take our chances and risk some crackheads relative hiring a hit man to attempt to kill a citizen who lawfully dispatched some thug. Then said lawful citizen will have the opportunity to add another notch or two.
Besides, it should pretty much be open season on hired killers anyway. In fact it should be open season on anyone who advocates their employ.
Keep in mind that normal, middle-class people do not get to hire contract killers. You might come into contact with somebody, but what will end up happening is that he will turn informant to the police in exchange for them ignoring some minor legal issues. When you hand over the money, they arrest you, and the contractor keeps your money.
Oh, real contract killers exist -- but they are only hired by people "in the business" who have the ability and willingness to PERSONALLY do unpleasant things to people who cross them, and only hire contractors to establish distance between themselves and the target.