"cross winds or trucks passing are a non event"
I must disagree. My grandparents Airstream and Olds 98 were rolled by a passing truck. They were upside down for two hours (they rolled in Arizona in the '70s, when there was less traffic) until a passing railroad repair crew happened by.
No trailer is immune to passing trucks, given the correct conditions. I guarantee they were not going over 55 mph, and had all the towing equipment available then, including a WDH, I believe. It's been years, but I do vaguely recall them showing the WDH to us when they first got the Airstream. It sure looked odd to me, and I had no idea how they worked. It just looked like lots of extra arms on everything.