Well, I agree on many points. Curses do work. I've been doing revenge, get-even and vengeance spells and curses for others who are afraid to do them for years. You must know exactly what you are doing, if not, don't do it.
I have my own theory why there is this "three fold law". It's because revenge, vengeance spells really, truly work so well - it's amazing - so much so, that there has to be some way to deter spell casters like me from doing them.
If in your heart, you really believe in the "three fold law", guess what - yeah, you're going to get it! I've been doing them for so long (we're talking years), with such great success, sorry, I don't follow it.
Anyway, I suggest don't attempt it, unless you are comfortable with it and know what you're doing.