I would be afraid the carrier would rub on the roof and scratch it. Also depending on how much "stuff" you have in the carrier the crossbars would give you additional tie down options and possibly prevent the carrier from blowing off the roof. I was behind a car last year and their soft-top carrier blew off while going over the Bay Bridge in Maryland. What a lousy start to a vacation!Hunt said:I would only use the cross rails once or twice a year, for family vacations. We use a soft-top carrier, but I'm wondering if I can use it with the side rails only, and not buy the cross-rails. The carrier attaches with straps on the front/back and both sides. It is typically pretty heavy, once fully loaded, and doesn't seem like it would move much, even if it was only secured with the sides only. Anyone have any experience or opinions on this? ???