During the snowstorm in AMS last year, we were stuck on a DTW-bound plane all afternoon, first at the gate, then in line waiting to be de-iced. I was talking with one of the FAs and she hinted that if one of the passengers asked to get off, the pilot may decide to take us back to the gate. I did so, and we halted our futile efforts to get de-iced. I don't know what rule prompted it, but at least we were off the plane.