I totally agree, but can you elaborate how? In my experience, they take your money first, punch your info into the state's computer, and only then start looking at the car.
In any such borderline situations, the narc to the state is the most troubling. I can't prove it, but I suspect getting a big red "fail" mark on a car's record is always going to be cause for future suspicion. I once found a tech (by pure accident) in Berkeley who offered to run a machine in "manual mode", simulating a test on the rollers while I watched the numbers on screen. He unfortunately is no longer in the business. Sure would love to find another such friendly tech.
Anyone with a suggestion, PM me? And I'll bet the OP could use this info as well.
Obviously, I would not expect a tech to spend the time for free, since an unannounced pre-test could be very valuable. Much cheaper than buying a 4-gas analyzer, when you want to have an idea of where you stand.