IMHO, your example is a tad different then the Candlelight Processional because the Candlelight Processional is a show with seats...and some there even pay for a meal to get better seats...but at the Castle show at
MVMCP or for example a band playing in Epcot, you can't really force the people around you to sit. Or if you have a curb seat for the parade and there are people behind you and you decide to stand, the people behind you can't force you to sit.
I just got back and at the Castle show at MVMCP everyone was sitting till it started and then most stood because it was hard to see it over the fake trees they put around the stage. I don't see anything wrong with that. I was at Epcot and a Beatle-type group was singing at UK and we went to take a peek. There were many benches with old people sitting and some people standing around. I accidentally got in front of someone on a bench and they yelled at me to move. I did but my DH told me I shouldn't have had to move.
Just wanted to give a different perspective. I don't think standing to see a show in front of the castle is exactly the same as standing at the Candlelight Processional. IMHO.