I'd actually label it as both of their faults. I'll give you an example from software development...
The product manager comes to me and says "I need you to add this field to the set of data stored for this thing". In the specific scenario I'm talking about, there's two ways it can go:
1. I blindly add the field for them. Later on, it turns out this field duplicates another field in that it can be calculated from that one. The fact that there's two fields that have the same "data" means that users get confused.
2. I ask the product manager what it is they're trying to accomplish by adding the field, so that I can make sure the implementation being asked for is the correct one. We find out it isn't and, instead of adding the field, we add an additional view of the data that allows the user to specify it two different ways. Everyone is happy.
My point is that the person going into the Apple store should make sure to describe what it is they are trying to accomplish, not just what they want the person to do. Similarly, the Apple worker should know to ask for what the person is trying to accomplish rather than implementing it. Both individuals could have done things better, both are responsible.