I lost mine 3 years ago on our new keystone laredo.. 2 small kid's bikes and 2 adult. Had no idea, until about 5 miles down the road someone honked, I rolled down the window, and they said "did you used to have bikes on the back of your camper" I will never forget that one. Yes.. cheap rack, cheap bikes, 4 bikes at that! Anyway, bumper looked fine as it had extra welds on the corners, and it was, the rack snapped.
So, the moral is there is a lot of bounce as many have said. I am sure you are fine with 1 bike, maybe 2 when secured properly to reduce bounce and a good rack and a reinforced bumper. Mine stay in the bed of my truck (but they get beat up that way) we also just bought a golf cart now, so I am looking at the Arvika racks, around $800 for a 4 bike holder I think.