That's largely a myth, at least in the US. Everywhere I've lived really needs a button or the "Walk" cycle is skipped to give longer turning times for cars. But

That's largely a myth, at least in the US. Everywhere I've lived really needs a button or the "Walk" cycle is skipped to give longer turning times for cars. But because of the myth, you get infrequent pedestrians who believe in the myth and just wait until somebody on either side actually pushes the button.