I've visited the UA forum near every day for about 6 years now and can't recall seeing more than a few posts about city or country advice sought.

Regular posters and forum mods are pretty quick to steer such VERY occasional off topic questions like that to the right area. Mods in all busier airline forums I am sure do the same?

Some Forums like Qantas are due to their much much lower post volume, and smaller core of regular users, a little more liberal in that regard for general oz related questions, and it seems to work for everyone. Air Canada is a little more like that too. No-one steers hockey questions and entire threads to NHL.com - be a riot if they did!

The problem with "stickies" and Admin notes etc atop forums is that if there are more than a couple of really relevant and super helpful ones related to that particular airline, the forum quickly looks cluttered, and less threads are on the first page.

I lean towards this being the call of individual forum mods to allow it or not, depending on the traditional tolerance in those forums and heaviness of posts in that forum rather than it being a TalkBoard issue. They have a better idea of thier own forums.

A firm rule that works for UA or AA might not be necessary or even wise for QF or AC etc.