Not applicable to those cloth toppers, but I just bungee mine down with minor tension. It's a thin gauge sheet of aluminum that I had cut to give me overhang on all 3 sides and one long edge with a 1/4 inch 90 bend so that it lays in the rain gutter.
I was gone all summer in another RV and I left this just as you see in the picture. I did NOT know Hurricane Harvey was going to happen while I was away. I wasn't really too worried about the slide topper, as much as the RV floating away.
The water line, when I got home, was about 1 1/2 inches below the floor. I can't find a single thing damaged except I now expect the motors on the electric stabilizers will probably not last. (They both work now)
I can't believe that sheet of aluminum stayed up there. But I do have wind-breaks on all 4 sides since I live in deep woods.
By the way, the insurance claim on the stick and mortar (My kids and grandkids live in it) is 6 figures . It's hilarious that my 20K tinyhouse came out of it with nothing but a nasty layer of scum all over it.