I've had it 'from the other side'.
When dc1&2 where in Y4 and Y5, they started walking to and from school without me. They walked together until dc1 went to 2ry.
In the second year of them walking together, I realised that I was no longer included in many group activities. OK, I assumed, it's because I'm no longer in the playground twice a day with the other parents.
It was only two years after that, when dc2 had also gone to 2ry, that I discovered the truth.
Apparently I had been incredibly rude and ungrateful to the mum who had been seeing my children home from school all year, because I had not acknowledged, thanked, or given her any gift!
She had been deeply offended at the end of the first year, but when she saw that my children were still unaccompanied the following September, she felt it her duty to look after them, despite my ingratitude and despite feeling that she was being taken advantage of.
Err, hello? How about talking to me about it? No, let's just grumble in the playground behind Life's back.
I knew that my dc sometimes walked with her (or rather, as they put it, with her dc), but that sometimes they walked without anyone else, and sometimes with other friends.
I neither asked not expected that anyone would take responsibility for them. I knew that some of the parents felt my school were too young to walk alone, but it was my and dh's considered parenting decision, which we take responsibility for.
Surprised it never appeared on MN, really!