See, here's the problem with this situation: If you have free will, you also have the power to surrender it, by agreement or simply by painting yourself into a corner with your own actions. That's what Harry has done. He didn't add in any stipulations or provisos when he pledged himself to Mab. Thus, again, I have to think that while Mab could choose not to dictate everything to Harry, she could absolutely order him to do anything with his full effort and he would absolutely use every resource at his disposal to do what she wished. She doesn't have to dictate every decision. He has no leverage. Harry willingly, deliberately, and pretty much as knowingly as any mortal can, gave up his prerogative to make those calls for himself, and in this universe you can do that and such an agreement will supposedly be enforced. Are you telling me he isn't bound by that agreement? If so, as I said before, the whole system of oaths and consequences governing so much of the supernatural world loses integrity and meaning and becomes more or less arbitrary. It's a cop out, trying to shield Harry in particular from the consequences of major blunders by authorial fiat, and it's no less a thematic issue from the book because a supposedly angelic character tries to make it out as anything to the contrary.
Now, I agree that this is no minor issue and would have have very problematic ramifications for earlier books. That's why I think the story jumped the shark when Harry made that agreement with Mab and when Butcher allowed the vow to Mab to be that all-encompassing. But I don't think we can just overlook it because we don't like the impact taking this problem seriously would have.
Molly was incredibly foolish. And I can't believe nobody ever seems to have warned her that Winter might take an interest in her or what the consequences might be of accepting their help. But she's biffed it big time now, and now I have the hardest taking any possible redemption for her seriously because she'd already biffed it big time and been given a second chance and she totally and completely and knowingly blew it, in a worse way even than she did the first time in ignorance. And Harry and the example he set and his associations with Winter seems to have had a great deal to do with all that. It doesn't appear that he ever gave her the kind of education in steering clear of Faerie entrapment she needed. And I liked her. More to the point, I love her family and hate what this has to do to them. That's why I hate that Butcher's done this to her and am tempted to stop reading if this is what he's going to do not just to her, but to her family. I read for entertainment, not to torture myself or watch characters I'm attached to be tortured.
Lany79 - People can talk about free will, but it's a funny thing. We have all the options we could ask for so long as we steer clear of the whirlpools, but once we choose to get too close, it's funny how how our options become extremely limited or just plain disappear. That's one of the sobering realities of free will: that we can and, indeed, must be able to do things we can't take back and that will have the worst consequences later on.
Personally, and this is just the way I see it, so I could be wrong, but I think that if you believe your Free Will can be taken from you, or you believe that you can surrender your Free Will, then you can. But I don't think it can be surrendered or taken. But we can be made to think that it can be taken or surrendered. If Harry believes that he has surrendered his Free Will, then he has, at least for that moment. But if Harry doesn't believe that, or if he then decides that he'll no longer be Mab's puppet, then he has a chance.
You're right in that Harry is in a tight spot. By the terms of being the Winter Knight, he is under a Geas to Mab. But that doesn't mean his Free Will has completely evaporated. His choices may be limited, but there are still choices for him to make.
And you're right, Free Will does mean that we can do terrible things that can't be taken back later. That would be a choice though. There's a choice not to act on the terrible thing. May not be a great choice, but it's still a choice.