There are one or two folk songs with whistled bits, like The Devil and the farmer, where you whistle the second line to make sure the D doesn't appear when you mention him. Whistling was quite popular in fifties pop songs (Guy Mitchell's Singin' the blues, for example), and a lot of British skiffle bands whistled because they were a bit short of instruments (expect some elaboration from Roger of that ilk!) And people like Bing were whistling well before the fifties, of course.

I can whistle very well (as good as Bing; vibrato, trills and all), but not in many of the same keys as can sing, so I don't get much chance.

If yo wnat to stop someone whistling, make them smile: it's impossible to get the embouchure! If that doesn't work, give 'em a fat lip ...

Steve