When we first bought our Destination Trailer, we decided to cover it. Our seasonal site gets a lot of wind during the summer, but the winds seemed to shift in the fall, so we took a chance. Our cover had straps that ran from the edge of the roof and hooked onto the bottom edge of the wall about every 6 feet or so and a strap on the front and rear to remove any slack.
We put the cover on in September, when we left for the season. In December, we checked on it right around Christmas. Almost every strap had frayed away part of the cover at the top of the trailer wall. We didn't have the time to really do anything about it other than to make sure the straps were still secure.
Fast forward a month and I got a text, with pictures from the campground owners, of our Trailer with the cover completely off. It actually circled the trailer. So it didn't blow off, it ripped down the middle at the top. Turns out, a tree branch just happened to fall on one of the vent covers. It poked a hole through the cover and the vent cover. During a windy storm, that hole in the cover expanded until it completely failed. Fortunately, the hole in the vent cover was in the half bath and there was no sign of water intrusion in the guest bath.
The sides of the trailer were fine. There was no chafe marks or any signs of damage. The roof, however, did have some damage. Where the straps attached at the roof, there were about 3 inch long slits in the TPO at the edge of the roof on the street side. Our trailer was 40 feet long and the cover had about 6 straps on each side. The curb side did not have any of this damage. There were 5 slits that I repaired with eternabond. There did not seem to be any water damage to the wood under the TPO and the inside was dry as well.
We did not cover it after that.
-Michael