"I'd love to ask, Saracen - you must find lots of people scared by autonomous learning - what's it actually like and are you ever scared by it at all?"
What's it like? Well, for my 13yo it seems to involve elements of 1) everyday life, 2) one long holiday and 3) the best bits I remember of school.
By "everyday life" I mean all the mundane things like supermarket shopping and playing with her little sister and helping with the DIY. She has done more of all of these things by virtue of just being around more.
When I say "one long holiday" I don't just mean the travelling kind, although we do travel more because we aren't tied to school schedules (at this moment we are on a month-long visit to my sister, for example). I mean having great long stretches of time in which to read novels or play or daydream. This apparently unproductive time does worry some people but it seems to give rise to bursts of energy and creativity and ambition too. My dd and her teenaged HE friends seem to have a deep sense of calm and contentment. It's hard to be sure where that comes from but I suspect that having so much time contributes to it.
I remember some good bits at school. Not many, because I wasn't a child who enjoyed school, but there were things that stood out. There were days out and visiting teachers who were fired up with enthusiasm for a subject which they successfully communicated to me. The funny thing was that I never asked to go back to those places nor did I carry on with the interesting subjects outside of school after the visiting teacher had gone. No time, for one thing, but mostly it just did not occur to me. Education was something that was done to me at school. After 3pm I did other things. My dd doesn't see it that way. If she likes a museum we go back again and again and again. She often seeks the staff out to talk to them, then asks me to take her to similar places. When she finds a subject she likes, she stays with it, sometimes for a day and sometimes for many months, then moves on to something else not because she is bored of the first topic but because something else has attracted her even more. Most things interest her. I think this is because nothing is forced upon her. (Occasionally she does have to sit through a dull lecture or even a day-long activity because it would be rude to walk out.)
For my 6yo who has special needs, at this moment autonomous education means just exploring her world through playing, in the same way that preschool-aged children do. That is the right stage for her now. It's key for me that she should be free to do what is right for her and not what would be right for the average child of her age. She's very into baby dolls and making wild Heath Robinson contraptions out of bits of household rubbish. I estimate she would be considered two years "behind" at maths if she were at school but since she isn't, she is cheerfully oblivious to the fact that some people would consider her mathematical skills deficient and would want to try to get her to "catch up". Why is it that pushing an academically advanced child to achieve even more when he isn't interested is called "hothousing" and is deplored, while pushing a child with learning delays to achieve what she isn't ready to do is considered an appropriate and necessary intervention? I don't buy it. I'm letting her play. The academic skills will come when she is developmentally ready and interested.
Am I scared by it? I think I might be if my children needed to go to school quite soon, especially if they had not yet acquired some skill which is important at school. For instance, it could be hard for an autonomously educated eight year old who hadn't yet learned to read to be dropped into school without that skill. Suddenly it would become a major issue since education at school is delivered and assessed in large part through reading and writing. But since I'm in it for the long run, I don't have to care at what age my kids acquire any particular skill, so I can afford to be laid back. When they are ready they learn astonishingly fast so there is no hurry.
My confidence in the effectiveness of autonomous education is based largely on seeing older children who have followed this path and thrived. Without exception the older teens are in education or work and are on course to achieve what they want to do. They have sometimes followed unusual paths to get there, which is no bad thing. They believe in themselves. They are used to taking responsibility for their own learning and are not daunted by the transition to adulthood.
So no, it doesn't worry me at all but that is only because I have been lucky enough to know so many kids who are learning in this way. It has come to seem entirely normal to me. If it appeals to you, then maybe meeting some older teens would be helpful to you too.
Other people don't seem too bothered by what we are doing anymore. I guess the proof of the pudding is in the eating and it is plain to see that my 13yo hasn't had a deficient education so far. Or perhaps they have stopped questioning it because we all seem so confident and appear to know what we are doing. Perhaps they now think I am such a confirmed nutter that they don't bother trying to tell me I am getting it wrong :)