I personally like Judy's paragraph that is sent home at the beginning of the
semester.
(You might like to tell folks where they can find that, Judy.)
It has to be signed along with my syllabus for 5th -8th.
So when a student acts up, I have him copy it in class.
I say "If you can copy this here, I won't have your parent's sign it." If
it happens again, they copy it and the parent becomes aware it's their 2nd
paragraph and has to sign it.
I have never had to send one home.
Brenda