In a perfect world, there wouldn't be any receptacles behind furniture. In reality, specially with rooms larger than a broom closet, no matter how carefully the original layout has been planned, eventually some pieces of furniture will end up in front of one or more receptacle(s). Even if in a total renovation or new construction the customer already planned the whole furniture layout in advance (which is not all that likely), it will very likely change at some point in the future.
What we can do is supply enough receptacles to make sure that at least some of them will (hopefully) stay accessible in the future. However, that's a design choice between the person who is going to live there and the EC. If the EC works for a developer, landlord or whatever absentee owner who will only pay for minimum work, minimum is what we can do. We can pity the future buers or tenants, but that's it.
