Why do OP’s not say they are not in the UK in the first post?

Edited - I just re-read your post.
Aside from the examples you mentioned - there’s really not a need to.

They may not think it is relevant. Doubtless people who repond will be quick to correct them if necessary.

Usually Americans assume everywhere is American, it doesn’t occur to them I’ve noticed

Maybe they don’t know this is a UK based site?

I had always thought it was slightly less than that, closer to 1/3? Given legal advice changes across the UK as well it would be generally useful for anyone looking for legal advice to state where they are based.

It often is relevant, I notice.

Sometimes you're not thinking clearly when you post. We all make mistakes.

I've also noticed that SOME Londoners are exactly the same!

Also, for legal and other authority-based advice, it's not even enough to know that somebody is in the UK, but which part of the UK.

It’s usually on posts where location is really relevant too eg asking for advice about access to healthcare, talking about schools, cultural norms around kids’ birthday parties etc. And then after everyone has given advice, they say ‘we’re not in the UK’ but don’t actually state where they are, as though they’re in the secret service.

I suppose they might not realise it's relevant - sometimes a thread can progress in an unexpected direction.

I tend to assume posters are in the UK if not otherwise stated, but I do look out for clues in language/terminology and check if I'm unsure and it's relevant.

Maybe it wouldn't hurt if posters would realise that MN is not a bubble, is not a UK bubble and posters are based everywhere?

Some UK citizens overseas, some non-Uk in the UK non uk citizen in a non uk country...

It's bizarre or very entitled to assume everyone is in the UK. English is not everyone first language either, maybe people would be less rude if they accepted that.

It's the same on Reddit. Unless you're in a UK sub they assume you're American. The OP also assumes quite often that people know which country they live in

Maybe it's just me, but I find it slightly irritating when people are a bit cagey and inform us that they're 'not in the UK' - and then they seem to resolutely refuse to say which country they're in.

You're not going to out yourself by stating your country - unless maybe you say "I live in Vatican City, I wear a white robe and I travel around in a famously-modified car". Even if it's not a majority English-language country, MN is big enough that there will be English-speaking MNers from (or who have lived in) most countries.

For all you know, you could go out of your way to avoid saying you're from Denmark, when there's a Danish lawyer on the thread who could have given you the exact 100% correct info that you were seeking!

I think it works both ways. It's a UK-based site, with a majority UK user-base; but it's also used by people worldwide.

Often, there's a good reason for non-UK people to point this out; but we also don't want fellow Brits sniping like a jealous child and asking accusingly why e.g. Americans or Australians are even on here, when they are just as welcome as anybody else is.

I translate it as not wanting to get a barrage of abuse and insults against that country and nationality, more than a will to be private.

Fair point, but the nasty people who respond in that way should be the ones getting deleted, restricted and banned if necessary - not the overseas MN users. It must take a very special kind of idiot to think that a random ordinary person on MN from any particular country is speaking on behalf of, and with the full authority of, that actual country as a whole.

Someone has just posted in another thread, asking for advice about airport checks, that they are flying to ‘one of the Balearics’. Classic mumsnet pointless secrecy 🤣

For anything legal, school system, healthcare system etc related location is essential, eg Scottish school and legal system is different. But not everyone is thinking straight. There’s a lot of British expats on here but they send to say eg I’m in Spain

Is that the one that has Ibiza in the title?

There was a thread asking for help with some aspect of procuring food a few weeks ago and after dozens of posts talking about Asda, Lidl, Sainsburys etc, the OP announced she was in Spain so it was back to square one.