Mr. clockert,
Sunny here. ;D.
When we were working at motorola, the county did not regulate a form but Motorola had a liability waiver form drafted and all of us signed that.
PM me for a copy of the form, although there might copyright issues, you could use the form for a basic idea of what to draft up. Since robotics itself is considered a school activity, all of the rules of school and stuff automatically carry over.
. But I'm sure you already knew that.
Let me know and I'll get you the hook up.