Being blonde, I have some idea what it's like to be discriminated against for my hair colour.
There isn't any basis for people born with blonde hair being considered less intelligent, in the same way there is no basis for red hair being an undesirable hair colour.
While the salon's sign will probably be laughed off by most, for red-heads who have endured a childhood of being called "carrot top" or "gingernut" it may not be so easy.
Some of the most famous women in the world are red-heads with gorgeous, glowing locks. Nicole Kidman, Adele and Emma Stone are all people I'm sure this Tauranga salon would be happy to have as their ambassador.
Surely the salon would be better offering people the chance to enhance their natural looks rather than reinforcing negative feelings red-heads thought they had left behind at primary school.
In most cases of bullying or discrimination it's the majority picking on the minority who are a little bit different in some way.
While having brown or black hair will protect you from the "ginga" jibes and jokes about your lack of intellect, it will also see you hidden amongst the majority.
Red-heads make up only a small percentage of the population. Why would any one want to "fix" what is special and rare to ensure it never stands out in a room?