I somewhat agree with White here. To a degree of reason we do have free will, but that doesn't mean we are not surrounded by actions that result from an infinite number of possible situations or the fact that as an interdependent species, social creatures, we are heavily influenced by other people, circumstances, and situations all the time.
I suppose my opinion on the matter is that affecting free will is a personal and ethical choice a person must make. Some people individually and even some paths or traditions do frown upon the act of intentionally affecting the free will of others. However with or without magic we are bound to do that already to some varying degree. I think the intent of the ethical perspective on not affecting free will is about not manipulating someone or people in general in such away that it causes that person or peoples significant harm. But you also have to consider that regardless of what you do magically or otherwise there will always be consequences for your actions, whether they are positive or negative consequences is left to uncertainty. With that said I think most importantly that affecting someone's free will is a matter of individual personal belief. Regardless of it being a common, universal, written law or otherwise a ethical guideline some people may or may not abide by,
It is ultimately up to you to decide whether you want to follow such a law or moral. Consider what you believe, why you would believe it, the reasons for doing so, and think about how it may or may not affect you or other people. Think about it like this are you a person who is willing to get something done because you want it so badly you'd be willing to obtain it no matter the people you affect, the consequences that may ensue? Or are you the kind of person who is patient, hard working, and thoughtful of others, enough to consider how it will affect them? So it really comes down to whether you care about other people, or if your just a greedy and selfish purpose, personally I am not judging either way.
Aside from talking about the moral implications of affecting free will, there is also the fact that free will is still just a concept and theory. There are many people who whole heartedly with out a doubt believe that we have free will. On the other hand there are people who will no doubtedly swear that free will is an illusion, a concept invented by man or whatever scores of arguments or reasons they make to convince people.
Locally thinking about it in an in depth matter you have to consider us as humans and think about our actions and why we do the things we do. Our actions and behavior are driven by motivation, a physical need or biological requirement, a emotional response or reaction, chemical interactions, our thoughts, our personality, and not to mention the countless interactions we have with other people everyday. With that said, does that mean we do what we do because we are driven to take an action either in response to something we need or want, or because we responded either emotionally or mentally. While that may be true, do we not have some sense of control on the actions that we take that end us up where ever we may be. Considering there is usually in most cases an infinite amount of possibilities to the actions that we take regardless of what motivation that caused the need for the action in the first place.