Holy crap...
Woke up from a nap and this got leaked out; all hell broke loose.
Okay, SO...to provide an official inside scoop on this policy...
Just to let everyone know, WDWMagic and every other website reporting the same thing is half-explaining this in the wrong way. I was given the update just the other day, so I'll give you guys a thorough explanation.
The FP+ policy for downtimes:
1) If an attraction goes 101 while you are in line and your FP has already been redeemed, you will have the same scenario as it is right now: You will get a physical FP readmission pass for use later in the day. This is something I imagine will change once the entire system comes online and FP becomes paperless.
Keep in mind: Under FP+, FP are not redeemed until you reach the second checkpoint, aka the Merge point. That's why those second set of readers are there.
2) If an attractions goes 101 BEFORE it is redeemed (aka before you get to the Merge point OR before you reach the attraction), you will receive notification and two things can happen.
This is the part that WDWMagic and everyone else is getting wrong.
There are two options that will happen:
1 - The first option given is that you can extend your FP+ for that attraction for the rest of the day and show up whenever you want to. It's virtually the same policy there is now when it comes to FP's during a downtime - if it's down when you visit, we'll honor them later.
2 - You are given the option to get another FP+ for something else. However, there's a caveat: If it is an FP+ for an E-Ticket attraction, you can choose any attraction on FP+...EXCEPT other E-Ticket attractions.
For example: Downtime at TT. If TT goes down, you can get everything in FP+ EXCEPT Soarin'. Same goes vice versa.
I imagine this will prove to be the case over at the MK when it comes to the larger array of E-Ticket attractions there.
As Steve has said, when it comes to downtimes, if it's past a certain hour (namely the last hour of operating day), there's a downtime situation and it appears unlikely to be resolved within that timeframe, you will be receive notification. You will be given an extra FP+ for any attraction at any park for the following day. In other words...you will have not 3, but 4 FP+ to use the next day. Woohoo!
While the other option is quite a bit of a slap in the face, the recovery option for the following day is a genuine plus of the FP+ system (IMHO, the only one so far).
Before anyone asks any questions, I'm gunna be answering some in the next post so wait to see if I answer your question properly...
Last detail to keep in mind: FP ratio at almost every FP attraction will be continued to be used as is: 80% FP, 20% Standby. Make that as you will...