This is actually a joint effort by the NBME and AMA to alleviate the shortage of primary care physicians in the less populated states. Any students taking the exam in these next few months have a projected average of around 200. Thus, most of the students in this group will only be able to match into family medicine in Idaho, or some equivalent state.
And I'm only half kidding.
Seriously, testing on information not in FA + UW just pretty much explicitly favors those people that have been able to retain information from their first two years, i.e. those students that did gunner training or are otherwise unbelievably gifted, while everyone else gets shafted and gets stuck with a 200. Even if you don't get a 200, you probably got 20 points lower than you could have gotten if only you took the exam 2 weeks earlier. At least if they added a section on interpretive dance, everyone would get questions wrong. But not in this case.
I'm pretty sure they state somewhere that you're NOT being graded on how well other people are doing. They standardize each test to some pre-determined scale, so that scores across all examinations are comparable, but not based on other people taking the exam at that time. Think about it. If everyone gets a zero for whatever reason, does that mean if I only solved 1 question correctly, my score would magically be a passing score? Of course not. This was the way they scored the MCATs as well.