I'd like more information to be available in order to help/ understand people.
I realise this is a complex issue because of invasion of privacy, but I think sometimes privacy isn't the reason information isn't given, and it's just that things haven't been thought through.
A new family who moved to our village asked if their 8yo DS could come to ours to play with one of my kids 6 months ago, after the boys had played together in the village playground. I agreed and we set a date a few days later, the parent gave me no information about her DS - sent him down the road on his own, which is fine usually - he was very, very difficult to have in the house and ignored the child he'd come to play with. I told the mum how he'd behaved and she just said "yes he can be difficult.
Just recently (6 months after the "playdate") the mum was in the playground again and we were chatting about her other child (small toddler) and she told me her older child had been diagnosed autistic exceptionally young, before he was 3, and had been excluded from school just before they moved to our village, and they were still waiting for a place in a special unit. I bloody wish she'd told me something before he came to play on his own - some tips on good ways to manage his behaviour and a heads up on how he would behave, rather than just ask me if he could come over to play, leave him to trot over, and then go to the shops so as not even to be contactable. It's a massive ask to expect people you barely know to guess something you've probably spent months or years getting the hang of, but if she'd given me a bit of information I would not have expected the same from him as from all the other kids I have through the house, who respond to standard teacher look / voice... It would also have been nice to help manage my own child's expectations, as he was utterly baffled by his "new friend" ignoring him and rampaging through the house taking his older siblings' electronics and telling me he was bored, DS was boring, and I had to let him play console/ screens every 3 seconds!
If the parent had been more honest I would have done my best to have him over again too - I can only assume she was desperate for a break and thought I probably would at least keep him safe... but it could have been better for everyone if she'd been more communicative (she chatted to me for ages about other things before asking of he could come and play).
Another of my DSs was on a school trip with a partner class in another school. There was a boy with special needs in the other class who DS felt was left out, but the children were told nothing about him and didn't know what to do - DS cried himself to sleep over the boy when he got home, worrying that the other boy was sad and that he should have done something etc.
As I said I recognise it isn't clear cut, not wanting to share your business is legitimate etc. but sometimes a bit of information about how to help would be appropriate/ good for everyone involved!