Our campground is slightly north of the Twin Cities area. 2-3 years ago we had a 15" snowfall over the course of two days, followed within a week by another 3" of wet snowfall. There were many ShelterLogic-type covers in the campground that collapsed, and my neighbor experienced a cave-in on his camper roof.
Let me state that his camper is a early 1980's model...I wouldn't think any newer models would have a major issue with snow, but in the case above, I'd bet some folks drove up to the campground to remove at least some of the snow from their campers. When I came up to check on my collapsed shelter, I saw probably 15-20 people removing snow from their camper roofs.
However that means at least 300-400 folks that did NOT remove snow from their roof...and I didn't see a ton of RV repair going on in the spring, so perhaps they were all ok.
When my camper was in the open, I'd usually track the weather and keep an eye on snowfall.