For those unfamiliar with Walt Disney World’s Fast Pass, please read:
An unknown flaw to this system was that guests could return outside of their given time stamp on their pass. You could not arrive before your given time, but certainly could arrived after your time window. Effective Wednesday, March 7, 2012, Cast members at the Fast Pass rides will allow a 5 minute early arrival and 15 minute late arrival but anything outside of those parameters will not be permitted.
Why the change in policy? Disney has been planning an upgraded NextGen Fast Pass system, which will require much tighter control of Fast Pass entry than what the current system offers for it to be successful.
Will this affect how you tour the parks?