This is really for the non-buskers or (like me) once-and-future (maybe) buskers reading this thread. I'm enough of a believer in Marion's peer-pressure theory that when I come across a busker doing a good turn, I'll try to guess who else coming along the street might profit by a good example, wait 'til they're in range, and then tip as conspicuously - and as much - as I can. Doesn't always work, but a lot of folks do need to be shown what to do...and what it is o.k. to do.