Why are you getting so worked up about it? You got your sticker somewhere else, next time go where they'll pass it and be done with it.
I've found the chain muffler places or those who offer bargain inspections are most likely to find something bogus to fail you on. Here in N.H. on a pickup if the exhaust exits past the cab (and there's no cap) it's legal. Got failed once for it, mentioned the law to the "service" manager, he basically said tough cookies, there's nothing saying they can't set stricter standards than the state. I knew arguing wouldn't get me anywhere so I cobbed together something to exit the exhaust out the side, then just took it off once I'd gotten the sticker. Lesson learned.