I get really tired of saying this, but please do not lump all Petsmart/Petco employees together. I worked for Petsmart for a year and a half and I am quite knowledgable about all the animals that were under my care. Perhaps the employees in your area are bad and that needs to be addressed, but in the store I worked in, my co-workers (with the exception of the managers) were knowledgeable about the animals in the department and knew what they were doing. It was only when we got a new pet care manager that knew jack diddly that things began going downhill.
If I hear pet store employees giving bad info, I step in and say something. Before I ever worked for a Petsmart I went into a local Petsmart near me (not the one I ended up working in) and a lady was asking questions about a leopard gecko. The employee was failing miserably so I stepped over and politely put myself in the conversation and the employee let me take over. If you overheard an employee giving bad husbandry advice, I would take it to the mananger and let them know the employee needs a bit more training. Of course, it is not the employees fault. Training materials are not very informative.