I am not an experienced glider pilot, but I can say that few airplanes will find straight and level flight hands off in a useful way. I certainly would not think of letting go as a tool for when I upset the plane. Long period return to more level flight could involve an overspeed, or overshoot of the desired better attitude. It is simply the responsibility of the pilot to avoid flying into conditions for which the plane or their skills are not adequate.
This is the reason that some maneuvers are prohibited in some types, not that they cannot be flown, but the margin of recovery without exceeding a limitation is too small.