I was going to offer my usual knee jerk answer of "Airzound" air horn, but that is not going to work here. I agree with Mr. Bill and wphamilton, report it (until it's changed) and yield. I have a few intersections and crossings in town where I know I have the right of way, but when I'm on my bike, I yield. It sort of feels wrong and makes me feel like a looser or quitter, but discretion is the better part of valour.