The woman is not been checked everytime because of her hair - she has been put on the SSSS list [1]. I am a white male with rather boring short hair and I am on the list with American Airlines (most likely because I used to fly round the world regularly - hint TSA - the world is a sphere). Interestingly it is only AA that SSSS me - every other airline is fine.
1. https://en.m.wikipedia.org/wiki/Secondary_Security_Screening...