Due to my book Death and Destruction, it is pretty well known that I'm counted amongst the magicians who will perform harmful magic and death spells. However, I rarely perform this kind of work in practice. Partially it's because I'm not often asked to perform curses (the only kind of spells I think I get fewer requests for are curse removal spells.) Additionally, there is the fact that of the few requests I do get for death spells, I wind up turning down about 1/3rd of them.
Why should this be? It's well known that I don't believe in karma. What other reason could there be for refusing such work?
There are actually lots of spells I turn down, and when I turn down a spell, whether it's a love spell or a plague of death ritual, the most common reason is because I don't think it's going to work, or at least not work in the way the client desires.
Many times, when I turn down a death spell, the primary flaw I see is that the person is clearly expecting fairly immediate results. I had one inquiry where a person insisted they needed a spell to kill a man because they were being threatened by him and it was "the only way" to be safe from the danger. Except, a spell might take weeks or even years to actually cause the man's death -- realistically there is even the possibility it could fail altogether. If you want the spell to provide protection against an immediate threat, a death spell is a very poor choice. (In fact, I advise never using a spell at all if you are facing an immediate problem that cannot wait, because spells so rarely bring instant results.)
Another problem I come across often with death spell requests is that the person is imagining that some other problem will be solved by the death. Again, even if you came to me with a request for a blessing spell or a money spell or a love spell and it was clear that you were having me cast the spell in hopes of gaining an unrelated or indirect intention, I'd turn you down just as well. On several occasions I've had requests for death spells in order to put somebody's love rival out of the way -- but I turn these down almost always. Why? Because, magically speaking it's not anymore complicated to just do the spell that actually would focus on the real intention (being, to win the desired love object.) Plus, there are many cases in the world of people who do abandon everything they have in the name of love, including things like money, child custody, status and citizenship. I bring this up because it is evidence that a person who insists that they "can't" be with you over fear of losing such things, really is a person who is choosing not to be with you and, consequently, might not stay with you even if they're unburdened of their existing partner/spouse. Then what was the point of that death spell you did, and all the sadness you brought the victim's friends and family, if the person you did it for still won't have you? This sort of underlying potential is why you can't count on a death spell to indirectly solve a problem.
In my view, the only time it's appropriate to do a death spell on someone is if the death of that person is the sole goal. Not the imagined consequences of the death, but merely the death itself.
I think in some cases, the person requesting the spell isn't viewing the magic as sufficiently "real" in the first place -- the long distance,the passing off of the task to another person, makes it seem like a fantasy game. Try imagining your situation this way: if you could be guaranteed never to be punished, would you be willing to murder this person yourself? Picture that you argued your case successfully to the leaders of every nation in the world, they're all agreed that you are justified in killing this person. You are presented with your victim, who is tied up and gagged and unable to fight you. You're given a blade which you may use to slit his throat or cut off his head or whatever you wish to do to him. Would you still be interested in committing this murder? If yes, good -- you are a great candidate for using a magical death spell. If not, reconsider whether this is really gong to be a good solution to your problem.