I agree about some of them being aggressive; however, I had a different issue in Epcot on our last trip.
My mother (in her 60s) and I were walking briskly with the rope drop crowd, and I wash pushing my ds in his stroller. A young woman (looked to be college age) jumped directly in front of my stroller, and I couldn't help but run into her ankles with it. We would have caused a collision had we stopped, and she did it so quickly that I really didn't have time to stop.
Normally, I would apologize to someone for hitting them in the ankles (having said that, I have never done it other than this time, and even that wasn't intentional), but I simply said to her "You should not be jumping directly in front of moving strollers."
She looked surprised, but kept finding 6" holes in the RD crowd to keep moving forward.