My local petsmart has has chams in the front tanks. On display, with a brief caresheet that doesn't address much of the true care needed. When I asked a salesperson, they informed me that they were "Dead easy to care for, give them a tank with a heat bulb and feed them."
I don't think all petsmarts are bad, I think certain ones need a lot of work. As long as you make sure to designate WHICH petsmart you are complaining about, there isn't any issue with sending off a e-mail, snail-mail or even a phone call to ocmplain about husbandry or lack of caresheet knowledge.
Maybe the OP could print some extensive caresheets to take in? Talk to the reptile section, and show them the NEW IMPROVED caresheets. Maybe they could fix the ones they offer, or stop bringing in chams until they are more ready to sell them responsibly?
And despite the fact that chams can change color, I believe that anyone that's seen one declining and ill can tell you about the 'sickly color' they can show.
Theresa