"Don't let your grey give your age away." Why not?
This salon is in my town and I don't think this sign is good kind marketing. Not everyone has a problem with being a certain age. I don't try to hide my age at all. Even for those who color and cover their grey, age isn't something about which to be ashamed. It might bring in the crowd who agrees with the sentiment, but it's a real turn-off to me.