Assuming the details are correct, that dealership deserves some bad publicity.
The sad thing though is that every brand has some great dealers and some astounding rip off artists. This guy has been mistreated by a couple of chevy dealers and does seem, from both blogs, to have painted all chevy dealers with the same brush. I would almost say that's unfair but I have to admit that i am the same way about with Honda dealerships. I have never had a pleasant experience in a Honda automotive dealership despite visiting 3 different ones in two provinces,and yet i Know that they must have good dealers, as there are tons of happy customers. Still I won't give the local guys another chance to be rude to me and am likely to leave any Honda dealer at the first sign of shenanigans. I suspect that for this guy, any sign of weirdness by any chev dealer will have him bailing on them in an instant as well.
Hopefully the dealer principal at that place, will straighten out the sales force, as much publicity like that will hit his bottom line. It is a shame that the manufacturers don't take a more active stance on these complaints. Instead of offering the standard "they are independent business's" stance, if they collected data and used that as criteria for renewal of franchisee's I would think the rip off's would knock themselves out of business or straighten up. Obviously some people complain for the sake of complaining, but if 20% of a dealers sales result in complaints then something is likely to be rotten there. With GM looking to cull dealerships, a dealer that brings GM's name into disrepute consistently would seem a natural to kick out of their network. I could accept a company telling me that while they are unable to help me specifically that this complaint will count against a dealers renewal possiblities. I would be placated to a certain degree at least.