Hi Cassie!
Thanks for your question. The good folks at
Disney do everything they can to ensure guests can move around the
theme parks as reasonably as possible, trying to minimize congestion and maximize comfort. This is the reason for the
rules and policies they're enforcing in terms of stroller size, prohibited stroller wagons, suitcases, folding chairs, etc. This is not to penalize anyone, it's only to allow as much opportunity for everyone to enjoy "The Disney Experience" with limited obstructions. You are correct in that the policy for strollers is the following: "Strollers should be no larger than 31” (79 cm) wide and 52” (132cm) long when measured across the widest and longest points."
Now, there won't be anyone running around the parks with tape measures, or sensors that will go off if your stroller is a little larger than guidelines, but Disney does ask everyone to follow within these rules to ensure guests (as well as Cast Members) can make your experience as memorable as they possibly can!
Thanks again, and have a magical day!
Terry