Nope. In group bicycling and auto racing, drafting helps BOTH the puller and the drafter. There's no reason why that would change for hypermiling.
I know for an absolute fact that this is true. As a street and road racer, there is nothing better than following a friendly racer as close as possible for long distances. Me and my friend trevor raced our manager every single night for the fun of it, traveling 25 miles between city limits. We drove from 120-150 mph during this time, about 5 feet from each other at the closest, prime road and level surface. We gained 2-4 mpg extra by drafting for both of us. And at high speeds, that's a HUGE fuel savings.
Drive it like you stole it. Then go faster.
Truckers are generally on channel 21. If you read about CBs in a textbook it will say that 21 is for northbound/southbound roads and 19 is for eastbound/westbound roads (or did I have that backwards?) but in practice they all just hang out and bull**** on 21, at least in the RI/MA/CT area.