Most people don't realize that the Rede is fairly recent. It was developed as a means of protecting newcomers who weren't 'advanced' enough to know when it was proper to use 'baneful magick'. (I have to be very careful with terminology here because it is easy to get misconstrued.) This was about the time when the mentor system started breaking down with the first big wave of interest in the Craft. Under the old mentor system a beginner would serve a form of apprenticeship with a seasoned witch, and many of the ethical lessons were imparted by way of example. It becomes difficult, if not impossible, to role model when you have one teacher and a group of students - which is what most covens have to deal with nowadays.
One of the implied ethical statements in "harm none" gets into the issue of 'degree of harm'. For example, if someone were to attack my grandchildren I would be obligated to stop that person with whatever measures are appropriate. The safety of my grandchildren would be a "greater good" than the integrity of the attacker's 'free will' - not to mention the integrity of his skeletal structure.
Another example would be that of the Cone of Power that was raised against Hitler in 1939. The people involved were all experienced witches and knew full well what they were doing, and why. They saw using magick against Hitler as serving the "greater good" than letting him have his "free will" and invading England. As I've mentioned in other posts; the levels of Service for someone truly following the Path of the Craft involves serving the community of which one is a part. The true measure of a Priest/ess is not doing the "fun stuff" like handfastings and Wiccanings, it is evident when the time comes for serious work; being there for others during a Rite of Passing, having the courage to do what is needed and not what is wanted, and to be willing to do the "dirty work" when it is necessary.
One of the things I wonder about from time to time is how commited people really are. In the US, for example, we have a very strong Religious Right movement. Their stated objective is to get enough influence in government that they can push their various agendas through. One of their agendas is the elimination of Church and State. If they were able to come to power, and would use "thou shalt not suffer a witch to live" in the literal sense, I wonder how many in the Pagan movement would still be here? My personal guess is that you would see a massive stampede to the nearest church so they could get "saved".