I would imagine the airlines, victims of this collateral damage by some negligent muppet, would wish to claim costs from them. Engine damage might not be fatal or catastrophic, but it will be cheap to fix in itself: and if there was a significant delay in px schedules etc. the cost could be significant. And there-in lies the rub; they can not identify these UFO operators because they are not registered.
Will those who are involved in model a/c flying tell us the regulations they operate under. I would assume they apply to drones as minimum.