Actually I think we do have enough evidence to codify how the laws might specifically work... if you look at the evidence shown within the DF, it's actually based around wither or not your violating free will directly... hence Molly was trained by Leah to use illusion and other non abrogating methods to instill fear as a weapon, as opposed to the original violations using fear. Or the fae themselves being in the balance, never going into the negative with Rent because of the equivalency methods they use combined with the fact they simply do not directly violate free will...
Random tangential, They never violate any of TWG's 3 weaponized powers either, in Duty they maintain a warriors sense of Hope. In keeping their word they keep faith and in respecting homestead laws they respect the sanctity of love.
You might disagree but youd be hard pressed to show me an example disproving such a connection threading the 7 laws with free will...
extended tangential, the 7 laws(and the 7 Courts) may actually coincide indirectly with the 7 deadly sins. Though the exact translation would take some bearing of mind, some are easier to see, like wrath=murder or pride/hubris=TT and others you have to wonder a bit at, like sloth=enthrallment or invasion of mind=envy... and some really stretch but still fit vaguely, like Lust(non physical definition)=reaching beyond the outer gates
If we use "free will" as the concept, I mean, "Free will" as we seen in the world of the Dresden files, then I must say that "entering another's mind" either with or without permission is not a violation of anything.
"Free will" in the Dresden files is not concern about making life easier. It is in fact the opposite. "Free will" in the DV declares that nothing can interfere with a mortal's choice making, but it does not protect mortals from interference from the environment.
Mortals has to make choices even if the information is incompleted, even if the information is misleading. People are allowed to lie, trick, scheme and manipulate each other and other supernatural powers are allow to do so as well. The restriction is only tightened on the highest eschelons of power like an Angel. Even so loopholes exists and it is intentionally designed that way.
A mortal also has to keep making choices and suffer the consequences of those choices even they are in pain, in despair or under duress. As long as the influence does not permanently stop or mame the mortal's ability to further make choices.
Only under the most extreme of circumstances would TWG and the angels will intervened, and the intervention most often comes late if it is viewed under mortal perspective.
Entering another's mind without touching or rewiring anything does not hampered someone from making further choices, it just perhaps make your life a lot harder. Rape victims has to keep making choices too. They can choose to commit suicide or to abandoned themselves or they can soldier on believing that there are still light in the world. That's the point of "Free will". "Free will" does not protect you from adversity. It actually forces a mortal to face those adversity under limited resources, triumpth over it and grow stronger and wiser in the process.
As I see it, any magic that is not permanent or cause permanent or long term damage in which the soul cannot recover by itself is not black magic. Potions are temporary, it mostly cannot last a day. Most magic cannot last long either. Every sunrise magical constructs and energies are rebooted. A few sunrise can wiped out 99,99 % of most magical workings. Not even Mab could defy this natural law. She cannot block Arctis tor away from the mortal world after sunrise for example. Only the enchantment in demonreach is sort of long lasting , and that it because it is continuously powered by the energies from the well.
This condition does not protect mortals much, but it does makes violation of "free will" by accident or unintentionally rather difficult. Most of the time, "free will" violation can only be done with intent. When unintentional "free will" violation does happened, the damage tends to be limited and recoverable if given enough effort. The taint is not a permanent hopeless case like Langtry asserted. Only deliberate violation with intent would cause permanent taint.