I have offered advice once of twice at my local lfs (large chain store in the uk shall name un named but im sure you can guess who),
generally the staff there are good but as with every job your going to have new staff who re not instant experts.
i was in one time when they had a new person in the fish section who was trying to help a customer who was asking questions about getting paradise fish for their tank.
I could see and hear that the member of staff wasn't too sure themselves "more erms and mms" than ive had hot dinners this month, but to my surprise they had the guts to say to the customer that they were not too sure on that species and couldnt offer much advice on the question,
the new staff said they would try and get some one else to help and off he went. as i was browsing myself i started a Little chat with the guy and his girlfriend who were looking to buy the fish,
when the shop worker got back he had said he couldn't find anyone to help, as he noticed i had been speaking to the people he asked if i had any knowledge on the fish, to which i had to reply "erm mmmm erm" lol but i sill managed to give some advice to both the guy and his girlfiend and the staff worker.
The store has a very small section of books they sell which give info on fish species some of the books or sale are not cellophane wrapped so i walked round picked up a few of the books and we started to track the fish down to get some info on it lol (being careful not to damage the books of course)
the store person didnt make a sale on the paradise fish but did make a sale on a much more expensive fish book and the guy and girl walked away with a good resource so they could browse the fish they like and see if they will be suited to their aquarium, also the staff member now knows that if no one else is around he still has a resource he can turn to himself for advice.