We composed and framed these signs in all of our rentals in 5"x7" photo frames and also include it in our checkout email when we thank them and return their deposit. We had to leave it in the rental too because some guests review us before they check out (before they get our email with deposit refund):
…our checkout checklist reads:
IMPORTANT: A full rating of all 5 stars means you were generally satisfied overall with no major complaints. Each star docked indicates something wrong that negatively impacted your stay; for instance 4 stars indicates almost (but not completely) satisfied. Travel sites regularly demote property listings with too many ratings of 4 stars or less. Please refer to the “Vacation Rental Rating” guide posted near the entrance.