It's funny that people think that all Apple store employees are knowledgeable about the products they sell. I have on more than one occasion ask a basic question and they wouldn't know the answer as they were working at a big box store. Of course they will go try to find someone else who knows the answer, but that takes time.
I have found that the majority of the staff in the store are there to ring up your purchase. Cashiers without cash registers. There are a handful that do know the products, but you can't easily differentiate them.
This is true also. There has been many a time I have asked a technical question to an employee the answer to which I already know and they have had to go to someone at the Genius bar to get help on answering. Considering their product line all their sales staff should have some technical understanding of what they sell.
In fact I applied to work at an Apple store a few years back and whilst I'm no expert I feel I have far more knowledge on Apple products then a lot of their sales staff. As it happened I didn't get hired which really baffled me as I had a lot of customer service experience. Having said that it was a blessing in disguise but I won't go into that.