Something to think about when deciding how many bolts/screws to secure your panels to the roof. I was watching a couple of youtube videos on boondocking and one guy was camped in the California desert and a 80+ mph wind/dust storm kicked up for many minutes. It blew his antenna and vent cover off the roof. He did not have solar panels on his roof but if he did I thing they would have been gone.
Another video a couple heads off into the National Forest and comes across a washboard portion of the dirt road. It was enough to rattle your filling out.
If you not planning on going off paved roads it may not be that big of a deal. Although several years ago I was heading across New Mexico and a freak windstorm came up. We got off the freeway and found a nice protected RV Park. We got blown around pretty good. Later we learned that they closed the freeway and several big rigs were blown over.
Kinda make me glad that I put the extra screws in my panels...