I'm not certain on this issue...but singing around the piano is, of course, a strong tradition in itself. And, for what it's worth, I practice (and have posted on myspace) English folk songs with electric-keyboards set on "piano" - playing just the top-line melody with both hands (in the understanding that English folk-music, at least, has, for centuries, been the repetition of a relatively simple melody, for singing and/or dancing).
P.S: singing Christmas carols around The Cumberland Arms upright-piano is always enjoyable.