In my opinion magic can be tested on others without any harm to free will.
For example, i once use raised energies and programmed them "____ is now approaching me to talk to me",(just to test) and energies took the shortest route possible and the person came to asked me what exercises should he do at gym.
For obvious reasons, one cannot go on and test heavy magic on others, but these small interactions, they can be used to test magic, without harming anyone or going against their free will.