OP is from CA! Hell yeah, I'd bolt that down, AND I'd cross brace it, too. Earthquakes do happen. I had a car on rollers in my garage during our so-called Nisqually earthquake in Seattle back in 02(?). My '78 Magnum skated several feet and I found it up next to my 67 Cuda. Fortunately, the layers of Hazard Fright shipping blankets saved them from making hard contact. and major damage.