I've had one come off on a serious washboard dirt roads. I now remove the LL prior to going into the dirt. It was not the Dual Lock that failed, it was the adhiesive between the dual loack button and the windshield. I install "new" buttons after that.
2007 BMW R1200 RT,
2002 Suzuki DRZ400S, 2000 Suzuki DR200
1985 BMW R80RT, 1975 BMW R75/6