Just make sure she knows beyond the shadow of any doubt, that we do not:
1. share hats, scrunchies, barettes, hairbrushes, sweaters, coats, scarves, earmuffs, headbands. . .anything that's been on or near anyone's head (including costumes at school, if they have that kind of thing)
2. put our heads down with someone else's (like whispering in ears, lying in the grass head-to-head, etc.)
Lice has been rampant in our neighborhood for years, and these are military-style drills in our house!
"Booger, can you use barettes at someone else's house?" "NO MA'AM!" "Booger, if Sarah down the street wants to play "Hair salon", what do you say?" "I AM NOT ALLOWED TO PLAY HAIR SALON MA'AM!"
We haven't had them yet!
Good luck!