What do you want if the user types "SELECT (t0.x || t1.x) FROM table0, table1 ....."?
I would like to second that request. Ok, sure, there are cases where the info is meaningless (like above), and should be blank. But in most cases, it IS meaningful, and extremely useful for tools (not so much perhaps for hard-coded situations, but do consider A report generator, or a visual query builder, for example)