There appears to be some confusion over how many original copies of music are needed. The school should own an original for everyone that uses the piece (student, accompanist, and director). That does not mean that you cannot use authorized copies during the performance and give the judges copies to write on (you should never give judges originals to write on).
For the sake of uniformity and in case of challenge from a judge on-site, I would say you that you need to bring the originals to the performance in case you are challenged. Just keep them in a box or something. Better safe than sorry.
