Lol, years ago I was at a dinner dance of a youth group I was a member of and had been for years all round the top table with the county chairman, it was a big top table about 20 of us, half way through the meal, he got up and tapped his glass and asked us this question "am I the only person on this table that didn't go to private school?"
I had just been thinking the same thing and was happy to put my hand up, just me and him.
We laughed and moved on, I am old enough to be before university fees, but lots of my friends went to private colleges, or da da der! Finishing school.
All lovely lovely people, those of us who went to the local comp, like said up thread, if we remain local, the fact we are from the same area, means we can jump to other points in our lives to find common ground. Such as did you drink at, do you remember such and such, I worked at.
That said I live in a city with only 2 less private secondary school than state, one of which is the most expensive in the country.
It's only used to catch you out if they are a nob, if someone's a nob round here I can normally guess which one of the schools they went to
no need to ask.