Rudeness is never acceptable, ESPECIALLY in a Disney-trained employee, but PLEASE PLEASE remember, cast members are also human beings...going through human problems, etc. Even if they are having a BAD day: illness, homesickness, nasty guests, ... they MUST keep a smile on their face and give guests a magical experience. Sometimes, that unfortunately slips. Think about how many thousands of guests they interact with on a daily basis. I'm surprised there aren't MORE situations that are less than "magical".
Just to put things in perspective, here's one story to consider from "the other side":
Our college graduate daughter, honors winner, world traveler, equestrian - working toward a lifelong dream of a career with the Walt Disney Company, was doing her job with a smile on her face (on this particular evening, it was trying to keep traffic moving in a very busy walkway and giving directions to confused guests). A guest and his daughter stopped in front of my daughter. She said, "may I help you?" and he pointed to my daughter, and said to his young daughter, "THIS is why you have to go to college! So you DON"T end up with a job like THIS!" THEN, to add insult to injury, he turned again to my daughter and said, "But, you don't have to worry, at least you're PRETTY." and walked away.... My daughter just looked at him and said, "Have a nice evening." She called us that night and said, "you would have been SO proud of me. I kept my cool!"
I only share this to let you know, as I'm sure you do, cast members are due respect, too.