I'm not in favour of this idea (hee hee, I'm the only one who's voted so far so it's obvious what my opinion is) for a couple of simple reasons:

First of all, some threads in this forum don't have anything to do with a specific country at all (Worst Airport in Europe comes to mind).

Other threads have to do with multiple countries.

I think that adding it as a feature to the forum would be overengineering and would like to unnecessary and annoying constraints - i.e., what would you do if your question was about Spain AND France?

The Coupon Connection forum is there to serve a specific need (with specific actions possible, e.g., "Have", "Want", etc.) but the needs of this forum are far more diverse.

I see no problem making it "best practice" with threads where this is possible and necessary, but making it required is a very bad idea indeed.

Plus, if you don't know which country Barcelona is in, you're in trouble.