They don't
Students manage each others
I'll tell you, if a little shit thinks he can just get between me and my coming food, he's dead

My school called it "Tuck" but I prefer Canteen. It was similar to what Ross said, the kids would sort themselves out, if there was a line jumper the rest of the students would tell them to go back and when it's busy you just have to wait or get to tuck early

They don’t, but it doesn’t actually really happen at my school, then again I’m in high school, so that might explain it.

In my school, there's a line for high school students and a line for middle school students. Some may hold a place for their friends, which is a super big group, but the lines remain somewhat orderly and there's a teacher to make sure the place doesn't get crowded. (It's a small building, no chairs)

Not in school anymore, but I used to get paid to work in the canteen at lunch a few days a week when I was. If we saw it we used to refuse to serve people, or other kids would call him a dick and no one would talk to line skippers

Usually the children look at it themselves.