I think it totally depends on the store. I knew somone that managed a Petsmart in downtown Mesa before I moved out here. He was actually pretty reptile-savvy. That was a few years ago though, and in a totally different area of town. Most of the time, you just aren't that lucky.
About 6 months ago, they built one a few miles away from me, and I troll there for furry supplies, and end up making my way to the reptile section pretty much every time. The people there know me pretty well to know that I know a tad about reptiles, and I've actually been asked to give husbandry advice to a few customers/new reptile owners... apparantly not very many "proffesionals" know that it is NOT ok to use pine, and it is not ok to keep a Kenyan in something other than, oh... sand? (come on people... Kenyan Sand Boa) :headbang:
They had a big sale on their corns, and since I was already there buying fish tank supples, I decided to look. There were about 12 corns in the cage. A few looked decent, but some were very emaciated. They had thrown a handful of pinkies in the cage and left the poor little ones to fend for themselves. Of course, the aggressive feeders got to them 1st... which is why they were much bigger and more established. I even spied on one of them scarfing on a new regurge.
Plus there was the kingsnake hatchling issue stated above... :nope:
Unfotunately, I think they just don't screen very well in most case. Most managers just aren't knowledgable about reptiles enough to know when those they hire are not as well. Maybe they'll up the bars soon. In rare cases, you can find somone that actually knows what they are talking about.
Its nice to see that there are a few employees on sites like this, or fauna, or even (shudder) kingsnake. At least they will be somewhat exposed to some knowledge, and have advice/experience at their disposal.