RE: At what point does it become UNETHICAL?
unethical is one inch farther than you know you will hit where you want to, from past practice and experience, and knowledge of current conditions.
I don't know that humans can make an unfair advantage. A leopard uses all its skills and equipment the best it can, every time. A human should too. We don't have sharp teeth, fast, silent running, a sense of smell at all, jumping ability, or any of the other things a leopard (or wolf, shark, etc) uses, so we use our ability to make products to help us and communicate teachings about how to use them.