I understand exactly why people do this.
I had it done to me, once (and I only know because they were crass enough to tell me!) when I lived in a very insular village for a few years, where not much happened, and there were very few new faces and we were the only foreigners.
I had so much of my own stuff going on at the time (young baby, returning from mat leave, DH and I both starting new jobs, plus the usual house move stuff) that I only realised years later precisely how unusual I must have seemed (and I was and am deeply ordinary, but not by the standards of there). This was an overwhelmingly ‘aspirational lower—middle-class’ village. Almost none of DS’s classmates’ mothers worked. They very quite invested in grooming, were extremely houseproud, very interested in house decor, and appeared to take an obsessive interest in one another’s’ houses. House tours on a coffee morning were common, and there was a lot of discussion of Quooker taps and kitchen brands. It was very homogeneous.
I think I didn’t ’make sense’ in their eyes. DH had a locally-famous ‘big job’ and I was an academic (which puzzled them.,as I didn’t ‘need to work’), and yet I didn’t drive, cycled everywhere and dressed accordingly, and our house decor wasn’t ’high end’ enough for our salary. We took the wrong kind of holidays. Plus we were foreign and they couldn’t place us socially.
I realised eventually that at least two or three people had been trying to find out how much money we had. I remembered one asking detailed questions about exactly where we’d lived in London, and thought she knew the area or something before realising after a few comments on our house that she’d wanted the information so she could look up how much our old flat had sold for. I realised someone else had been looking up my university staff page when she started asking me about Oxford and saying I ‘didn’t seem the type’ — no one in this village would have known where I’d gone to university decades earlier. They had to have looked at my staff profile page which included qualifications.
In the end someone got drunk and told me a couple of them had been combing the internet for information. And this wasn’t friendly curiosity — it was an unwelcoming place in which my friends were made mostly via work.
It was pure nosiness about where to ‘place’ people who didn’t meet their idea of what a household with a joint income of £170 k should look like.