Hmm think I have a better idea of what happened then: Either the aircare attendant didn't know how high the truck was revving because they weren't used to vehicles without a tach, and should have shifted earlier, OR, your friend doesn't know that it's normal for the truck to rev higher than she usually drives it. I'm sure it's 1 of the 2 scenarios, and knowing some of the aircare techs, it could easily have been either case! :)

I've complained and had Aircare re-test a vehicle back-to-back because the driver was an ass - and passed. There are lots of ways to fail a car through driving styles. If you drive at a low RPM and lug the vehicle emissions will rise. Another one is constantly going on/off the throttle while trying to maintain a constant speed instead of keeping the throttle in one position. That really drives up the emissions on some cars (you can see the peaks on the driving trace).

Usually higher RPM's will help a car pass. One of the oldest tricks around when you fail the idle test is to bump the idle speed. Too high, though, and Aircare will usually say something.