I've got a feeling this wasn't planned. Emergency, necessesary, etc.
I've been noticing over several trip reports that there have been quite a few sewer trucks around the Fort lately.
(Near the Settlement, in 600, etc., etc.) They also did a bunch of digging on the backside of 300 towards the old cabin and the old Swamp Trail.
The Fort Sewer system was put in over 30 years ago, and the entire Disney property in on a swamp.
Any change in a swamp can probably cause problems elsewhere and perhaps they finally figured out all of the recent, frequent sewer problems has it's source in the 200 Loop, so they are fixing it. They may have no choice.
What will probably happen is that if they have a capacity problem, they have probably told reservations to NOT open up new availability when cancellations come in. (Cancellations will come), and then upgrade anyone scheduled for preferred that they can't fit to Premium.
Problem solved.