Annette-
I have class leaders and then rule leaders. For example, my rule 2 leader is responsible for rule 2, however they do not mess with the practice cards. They will simply say "Rule 2" when they hear someone talking a lot without permission to speak. I haven't yet had any of my leaders try to take over the practice cards though! I agree with you, Farrah, and Jon about just nipping it in the bud and letting the class know that you handle practice cards! Good discussion though and way to get that out there. I'm sure that other teachers have had similar experiences or will sometime in the future!
Thanks,
Staci