Fortunately cable failures are pretty rare, but they are not unknown. There was a fatal accident in Australia two or three weeks ago that has generated a lot of discussion down here and appears to have been the result of a control cable issue (not an RV). I understand that the FAR's require certified aircraft to be able to be flown in a stable attitude without the use of the primary longitudinal control system. RV-12's are designed to ASTM standards so presumably they don't need to demonstrate this behaviour, but it would be useful to know what would happen if one of the cables or linkages did fail, and whether trim and power could be used effectively to try to get the plane down safely.