although i know a lot of people dont agree, tattoos, piercings, and hair styles do not dictate what kind of person you are. it also doesnt dictate what kind of employee you are/will be. i understand looking "professional", and i feel at times it is absolutely necessary. BUT unless these things cause some sort of risk, they are just that! these people know they cant get jobs with 3 facial piercings (unless of course it is a tattoo parlor!) or blue/green/magenta hair.
so it needs to be clearly documented that rules can change due to renewed security measures/threats, and changing styles. if i go into a job with that secured in my head, by all means, tell me to change it when necessary. ill still be upset but not as much. and im also not in any position to fight it or sue either!