IN ZRH airport (terminal B = SR&Qualiflyer partner), upper level = check-in aerea, at the economy desk just one desk to the right from the 'family' check-in area is a monitor listening all (same day) overbooked SR-flights and asking for volunteers.

Thanks to Rudi's mention, this monitor was the first stop for me as I checked in for my recent ZRH - AMS SR flight. But, alas, no volunteers needed.