Some kids are seriously rude these days. What do you do if some really power-hungry sophomore (it’s usually sophomores in high school) chuckles when you try to make the Classroom Rule process work for you?
Such a thing would rarely happen in the first week. Usually the oppositionally defiant kids wait and hide until going into attack mode, while they make their decisions about how much personal power they see in you and decide to test it (yes, they do this consciously).
If and when it happens, be ready. Don’t talk to them as if you think you might be able to talk them into behaving as you wish. That is pure folly. You can’t reason with a drunk and the culture in some schools these days is one of a kind of social ivresse.