that you have to have a state license to be an RN. Just like lunch room workers, bus drivers, book keepers, etc. can't use the Teacher discount, only true nurses are to use the Nurse discount.
My wife is a teacher and they really looked over ther liscense when she checked in and even recorded the state and issue date. They said they were having to crack-down on this since so many have tried to take advantage of it by lying, making false forms, etc.