The posts you referenced never have the qualification that "only domestic travel agents/car mechanics/computer engineers/relationship counsellors can post" do they? They ask for general opinion in the hope of gauging some sort of consensus. If they ACTUALLY want the car sorted out they'd take it...
Why post it on a football forum then? Why not ask some economists? Or do you not actually want answers, just a weird feeling of superiority? And why should you believe what someone claims as their job. I'm an economist and market player. Now I'm a king. Now I'm a farmer. Why would that matter...
You realise that the replies you get to any thread you start aren't under your control? You ask a question and get answers - there are no restrictions as to what they can be. It's the joy of 'discussion'.
What you're trying to do is put boundaries around what can be discussed so people have to...