I remember the kids who got caned were viewed as especially tough and to be feared/respected when I was a kid.
The best way to reinforce discipline is to offer the kids a privilege/treat that has to be worked for and can be withdrawn. Kids behave if they think there's something in it for them.
Good teachers don't need to "reinforce discipline", especially in Kindergarten. Kids aren't prisoners... they are kids.
Kids want to be good, and they want to play and have fun. A good teacher sets up engaging activities and a environment where kids and learn and interact. If a teacher does that, he might have to give a little direction to a kid here are there, but he will never have to enforce disciple.
I have seen good kindergarten teachers. They set up their class a community that includes all of the kids. They don't have discipline problem because all the kids want the community that works... you don't rebel against something that is working for you.
There is no problem with sending the good kids to Harry Potter world, as long as you aren't excluding anyone. If there are kids who don't get to go to Harry Potter world, it isn't because the kids are "bad". It is because the teacher is bad. Excluding kids from a class trip is a pretty cruel punishment... imagine how you would feel if your kid were excluded.
By the way, I can't let the word "caning" in Izzy's post go. What a screwed up system!