I have a bike bag for my bikes. It works very well. It came from walmart.
The issue with my previous bike rack was the whip effect. Extension 4 feet, rack upright about 4 feet, bikes maybe 100 pounds, then a whip action when hitting the equivalent to a speed bump at 65 MPH. It ripped the metal beside the weld where the upright part welded to the stinger. I have no reason to believe this is a common issue, but with the safety cable from the bikes to the ladder will prevent to bikes from bouncing down the highway. The cable would not prevent the whipping action.Kinda like safety chains on a trailer. I use them, but never had a trailer hitch break.