I have the students copy the rules, rewards, and consequences of our class on the first day of school. Parents must read and discuss with their child, and both parent and child sign and return paper to school. This has drastically decreased instances of parent of student arguing about the rules.
I have been teaching for 12 years at a small Catholic school. I have always taught 5th grade. One of the great things about teaching in a Catholic school is having the time and the autonomy to be creative!