I'm surprised that some of the more well read members of this group are not familiar with the phenomenon the salesman from Nitto was trying to describe.
It was first noticed in the 20's by German and French aircraft engineers, the Germans were attempting to lighten non stressed braces on Zeppelin frames and discovered that certain OD's and wall thickness would vibrate and eventually crack. They went to stamped and formed aluminum parts.
The French however were determined to the replace wood and steel frame members with aluminum alloy. They eventually discovered that by wrapping the alloy tubes with a woven cotton fabric and coating it with shellac they could reduce the cracking to a minimum
Sorry, I've been painting walls all day.