Early. Frequently. Consistently.
If you make an absolute nuisance of yourself, the parent will either correct the behavior with the kid, or will demand that the schedule be changed. If a kid is completely out of line, every day, in your class, call the parent every day, let them know what they did. Follow up with emails if you can so you have written documentation.
In some cases, I was calling a parent virtually every day. Once, I did so until the kid came back the next day with a pillow to sit on. The parent had taken a switch to his behind. Didn't have a single problem out of the kid from then on - and he wound up being an All-Region player by 8th grade.