Edit: In the question I linked to, the dublicate was accepted by the OP. However, there are other questions like this one How do academics (faculty members, PhD students, etc.) balance their work and life? which are closed as dublicate of an US question. The current answer here talks only about the other question (which was closed by the OP), not about the other question or the general case. So the question is still unanswered.
Today, the following question was closed as a duplicate within an hour: How will several Cs and one F affect my chances of gettting into a PhD program? The questioner forgot to mention their country and the question was closed as a duplicate of a question "How to get into US PhD programs with bad grades". What I find strange about that is that there was no mention at all of some country, yet it was closed in favor of a question which has "US" in the title. The same happened last week with a question about work-life balance.
I find this really strange. I mean, even if it is statistically likely that the question is about US, shouldn't one give the questioner a few hours to edit in their country before closing as a duplicate of an US question? Or close it as unclear because the country is missing? Or is "US" somehow the default country we assume when there is no other information?
Just a note: I remember some answerer saying (about another student) something like "I assumed this was about the US because teaching assistants are mentioned". I don't think this is a good argument - in an English speaking forum, I would probably also use "teaching assistant", "grades A to F" and so on even if my home system does not use those words (when the details are not important).