To pick up michaelr's point above, (thread creep?) so many things happen in the world that some of them are bound to coincide with each other. Think of all the times people don't die when a song is sung.

It's supposed to be bad luck to play 'The Flowers of the Forest' at any time except a funeral. How do you practise it?

I once, at a loss for a song to sing (NOT a common occurrence!) sang the ballad 'George Collins' - which someone said was supposed to be unlucky. I forgot the words halfway through. Bad luck? No - I hadn't practised it.

Steve