interesting question...if you are out and about, and the anthem begins to play, and there is a noticable change in behaviour of the people around you, then the answer is probably to do as the romans do I imagine such a rule would apply, and I would err on the side of caution; that and it's just the nice thing to do...but if you don't know and no natives are there to emulate, then who is going to penalise you?