My jeep was a Cherokee. Unibody. I'm not arguing with you, you are right. They make a dual dirtbike carrier that I would never consider putting on a 600lb tongue for the very reasons you stated. Even though without considering things like bounce and distance from the receiver, the stated rating implies it shouldn't be a problem. I just know that nobody is going to have a problem on an X5 with a bicycle rack or a cargo carrier.