Kids running up and down the hall in the middle of a night, splashing water out of the pool, climbing light poles and having tantrums while in line. You all think this is bad behavior? Do you people even have children?
"To discipline" means "to teach." The time for teaching is NOW, any age, everyday, anywhere, including WDW.
We love our children enough to take the time to teach right from wrong and what is acceptable and appropriate behavior. We want them to be happy, now and in the future. They have to follow rules everywhere they go... school, sports, work, a friend's house, etc., and live by the laws. If we allowed them to do as they please simply because they are children, it would be setting them on a crash course with the world. At what age would we then decide they need to be accountable... 16, 18, 21? Surely they would be in for a rude awakening by then. How is it best for the children to let them be the kids everyone dreads being around, the kid the teacher doesn't want in their class, the one no one wants to play with? People, kids and adults, who can get along and are well liked and respected by their peers are generally happy individuals.
Tantrums are a means for getting one's own way. Other than special needs children, any tantrum throwing should end by the time a child can verbally express themselves. If it continues beyond that, it's because it is effective, it's working for the child because it working on the parent.
As for kids running up and down the hallways at night... my kids wouldn't be allowed to run up and down the hallways during the DAY, either. There are plenty of other places for running around, the common area of property owned by someone else is not one of them.
Yes, I have children, ages 30, 25, 20, 13 & 9, plus a 6 month old grandson and spent more than 20 years working with children ages birth - 6 years.