I am quite keen to hear correct attributions (but not a lot more) of contemporary songs unless there is a particularly pressing reason (Richard Matthewman's "Run the tide" about his mother's Alzheimer's disease being an example).

As for traditional songs I am very keen to know the historical context if there is a detailed one (Rufford Park being a very good example).

If the place is one where it may be appropriate to play along, a clue (and a key) is very useful - little gestures about how many sharps or flats don't help most of us much.