I would just guess that people may find it to be too noticeable. Some people in regular vans dont want to be noticed as they like to be "stealth" and camp where it's illegal. Go to an RV store and ask to take one out and put it up there and stand back and look at it. I like them on my 5er because they protect my flimsy lids from tree branches (12' 10") and let me have the vents open in the rain. They are much sturdier than the vent lid and and help with uv damage on the lid. If we had a bad wind or hail storm I think they would hold up much better than the vent lid.