Some people suggest I'm projecting feelings onto DGC. Not so, I think. As I said in the OP, DGC 'shrank away' from the stranger's touch. This particular child definitely just doesn't like strangers touching her. It freaks her out a bit (she's barely two, though in some ways old for her age). She engages possibly more than most of her age (ime) with people around doesn't really worry yet if her conversational gambits go unnoticed, but continues to try to talk to people when rebuffed; says 'Hello' and 'Bye-Bye' to all other bus passengers, as well as a smiling 'Thank you' to bus drivers as we step down; she asks strangers 'Why?' questions (not always appropriately - 'Why is that crane yellow?'); she tries, and sometimes succeeds, to get other people to join in her singing (mostly nursery rhymes, but she does enjoy singing 'It's a Long Way to Tipperary' and 'Pack Up Your Troubles in Your Old Kit Bag' some of the recent brass band concerts we went to at the local Cenotaph were a real treat for her as she recognised these tunes); she'll offer her toys to strangers, too (mostly grown-ups don't want them and other children around her age don't seem to notice!); and she understands compliments and will often preen in that unselfconscious manner lots of children do around that age when they're offered compliments. She just doesn't like being touched by strangers and at her age there's little she can do to avoid such touching when we're out and about. (Don't get me wrong it's far from a frequent occurrence.)
So, what should I do? It just seems to me not sensible to try to socialise her to accept random strangers touching her at her age and development.
And, does the fact that a child doesn't like being touched by strangers change anybody's mind, I wonder? Lots of people, children included, perhaps enjoy a stranger's touch. Those of us, children included, who don't -- don't we have the right to not be touched?
It's not at all about possessiveness, either. Possessiveness in human relations militates against autonomy, of course. What I want for my DGC, at the end of the day, is what I always wanted for my own DC; that they grow up to be (1) decent, (2) flourishing autonomous human beings, (3) successful in worldly terms if possible in a way that doesn't conflict with (1)&(2). (It worked well with DC, I'll claim.)
The complaint that barring casual touching militates against communal fellow feeling, promotes deleterious social atomism and so on; I'm sensitive to such thoughts (again, at least I think so, pace those of you who accuse me of not considering any of the criticisms I canvassed). It seems to me, though, that we can have social cohesion and solidarity without allowing random invasions of bodily autonomy. One of the things I thought we might have learned as a society is that people should be treated as autonomous beings as much as possible ... and that children are people too. I characterised the matter as one of 'right' to try to frame the discussion in the way suggested by that.
Again, sorry for the length and thank you for your contributions. I'm sad to read some of you saying I haven't paid them any attention. I have. I may not have paid them all the attention their proponents think they deserve, but, well, desert is always a difficult matter to assess. And thanks anyway.