My understanding is the EPA doesn't do the testing and approve the window sticker numbers, they set testing procedures and generally trust the manufacturers to adhere to the guidelines. They basically audited Hyundai over their recent claims and found them innacurate, and Hyundai admitted they screwed up their testing procedure, which miraculously improved their numbers.
The only recent car I remember consistently beating advertised estimates is the Jetta TDI, if I remember correctly it's rated at around 43 MPG highway and journalists routinely see significantly better mileage, nearer 50 MPG.
All that said, I will shoot myself in the foot if you can prove to me you got 47 MPG in a Fusion hybrid. Short of extreme hyper miling techniques, that number has always sounded like utter bullshit to me and I'm not a bit surprised Ford is taking heat over this, and I really expect these advertised numbers to be revised shortly.
Do you guys really think Ford has the ability to produce a cheap midsize sedan that can get near that mileage claim?