Yeah, I'm.... not buying it.
I regularly draft vehicles and there's absolutely no need to be that close to even a mid-size SUV. A large commercial vehicle like described in the OP? Yeah, they give you a *huge* pocket and being within 24" is so unnecessary that I have a hard time believing that someone would do it. It's much, much easier for me to believe that an observer would greatly exaggerate the following distance for dramatic effect.