They are selling a product, they are expected to explain what that product is. As WagnerPaiva says, customers are going to be very angry if they buy something and they suddenly find they cannot do something. Let's be honest customers can be idiots.... I do feel sorry for retail staff when they have people getting angry/shouting at them for stupid things.
So basically i agree, its their job to educate the user, because they will be the first people who get the abuse when little johnny wants to trade in a game and it all becomes difficult. If i was in retail, I would be pushing them to the PS4/Wii-u because its the same as before, not difficult to explain... while the XboxOne is a confusing mess right now..too complex for its own good.
Making an indie game : Dead of Day!
