A person should at least have some idea about what they are getting when they walk into the place.
A lot of places have at least one good person that knows their stuff. The rest seem to know some. Then again some of the kids they hire are either working there cause they need the job or they are learning the hobby. So they are learning right along with the customer.
When I go to the lfs I may ask a few questions, the first ones that I ask I know the answers to. If that person answers the wrong way I just go talk to the next sales person

If there is another sales person there.
These places are in it for the business like any other place, they want to make money. But if a customer has done some research they should at least have some ideas of what they are doing, and not rely soley on the sales person. There are a lot of resorces to read and ask about the hobby. Books and places like this on the internet where you can get help from people who are not looking to get money from ya
If a customer sees somthing they really want and they are not sure how to take care of it, they need to read up on it BEFORE they get it.
I have been at pet stores and the guy that knows saltwater will tell them "No your tank is way to small for this fish" the people get mad.
So I guess I'm say yes we do expect to much from the lfs.