I'm confused about the concept of "benign neglect” in relation to unschooling – is it a good thing or a bad thing?
It is confusing! Because unschooling isn't about teaching or leading on the one hand or following on the other sometimes it's described as "getting out of the way and letting kids learn" which would imply a kind of neglect - just let them do whatever they want. And there absolutely *is* an element of that in unschooling! But in another sense, it's not that at all - it's not throwing kids out into the world with nothing and leaving them to flounder. It's not ignoring them, shooing them outside (or over to the tv) and trusting that everything will be fine. It's not those things because kids are people with thoughts and feelings and perspectives of their own, and one of the fundamental perspectives of children is that parents are an important part of their lives.
This is always, always the central question of unschooling: what is your child's perspective? And one of the central tasks of unschooling is to hold that perspective as just as valid as your own.
With your child's perspective in mind, sometimes it's appropriate to "get out of the way". With your child's perspective in mind, sometimes it's appropriate to lift them up to see (as it were), or offer a better tool (I think of Morticia Addams taking away Wednesday's cleaver and handing her an axe!), or provide a comforting shoulder, or suggest a different perspective entirely.
It sometimes helps to frame things in terms of adult friends to gain a better understanding of what it means to consider your child's perspective. Your adult friends and relatives probably do stay out of your way and let you do your own thing. Those who don't (if you have any of those) you no doubt find irritating and frustrating - why do they have to be such busybodies? Why can't they get out of your way and let you get on with doing your thing? On the flip side, though, you may know a friend or two who's rather neglectful of your friendship - they don't stay in touch very well, aren't terribly "available" in terms of support. A good friend may be sometimes a busybody and sometimes unavailable - we're all only human, after all - but is someone who tries to value your perspective (thoughts, feelings, needs) as equally valid to her own. In that sense, you can see the goal of an unschooling parent is to be the best possible friend to our kids.