If you're still reading after the title of this post, you won't regret it.
I have a little girl who is fairly mature for her seven years. We'll call her N.
I typically dismiss my kids to do anything in small groups by saying things like:
"You may go if you have...
...pink on your shirt."
At dismissal time today, I did this as usual, but I added (for giggles), "You may go if you have hair."
N goes, "Yeah, Mrs. Overman, if Brittany Spears were here she'd have to wait till you said 'bald.'"