How do school uniforms help identify intruders?

School uniforms help identify intruders when students all wear the same outfit. For example if the school uniforms are green and purple and then a man walks in the school wearing a neon orange tuxedo the school administrators would know he did not belong in the school. Also, if he had a weapon he would have no place to keep it because tuxedos dont have pockets. Also, if he had a pocket in his underwear it would be very uncomfortable so he would not carry a weapon.