When I played FFXI most people with the mentor symbol just had it for the novelty, to make themselves feel special. Most of them were particularly unhelpful.

In FFXIV, I've mostly have just seen people ask questions in /say and usually get a good answer. Personally I don't bother with people, but new players (or returning 1.0) that have sent me a /tell asking something I've always helped answer best I could.