Imagine you go to the theme park at say 3pm, excited to spend the next 6+ hours at Epcot. There are 2 major attractions here, Soarin and Test Track. You are willing to wait standby. You get into the park which closes at 9, and walk over to Soarin where you are told "Sorry we gave out a card that says what time you can get in line, but they ran out an hour ago".
So that is what happened to people,and apparently it was not pretty. People are willing to wait whether it is 10 min or 100, so leave it be.
The difference with this an Anna and Elsa, is that people are running in droves to do see them....and the lines are affecting other things in the park. Wheras at Soarin, it just affects those waiting in line at Soarin.
(and in my opinion, many know that it's so hard to go and see the ladies, which makes people determined to see them, and i am willing to bet in some cases some people who would otherwise not care to see them are trying to because its the thing to do)