If it helps any, I've been carrying bikes on the roof for over 40 years with no incident. I like the steelhead type racks because they are so secure. No lawyer lips on most of my bikes.
Before the Yakima and Thule racks I had a rack with a separate tray for each bike that slid into rails on the rack. First you removed the tray from the rack. Then you clamped the handlebars and the seat to the tray. Then you turned the bike upside down and slid the tray into the rack. That was kind of sketchy. On bumpy roads the wing nuts that held the clamps to the trays could loosen.
Brent