The article, link above, is great!

I've had concerns about this, while adjusting a chair some years ago I read the weight limit posted. It was lower than I expected, and quite honestly hadn't thought about "weight limits" when we were running around measuring chairs to accommodate my large size ladies (I'm no pixie myself). I wondered, do I dare ask clients about their weight? Imagine. If they are over the limits and are injured as a result of "chair failure", in addition to my concern about their safety and well-being, am I responsible to the salon to replace the chair and to the client for repair of injuries for not preventing them from sitting on it? Do I post a notice saying the chair will legally hold up to ___ lbs and that clients over that weight sit at their own risk?
Large clients can be very steady pedicure customers, they sometimes cannot reach their toes comfortably and it is important, particularly when combined with other health problems, that they attend carefully to the care of their feet. Many professional women have told me they feel, because of their weight, they need to be extra attentive to their appearance.

I wonder if, reading the news story, that this situation may have been the result of a cross cultural event. People from different lands sometimes have a different way of approaching a situation. It can feel even more severe when a client is sensitive about a condition. I remember a facialist once said, loudly (smiling), to a young client "I can wax off you mustache?" The client burst into tears.
The facialist was completely confused. She was used to people being more open about things like that, saying she came from a country where having a mustache meant you were growing up. Was the manicurist above intending to humiliate her or concerned or her safety (and liability). Just because she had sat in chairs of that size previously, it did not mean that it was safe. the other salons may have been remiss in regards to her safety. Perhaps the law suit will bring out all the details.

Weight prejudice, like other prejudices can work many ways. If all parties are willing to be open minded, consider the others conditions and intentions and want to work things out, often things can be understood and brought to mutual satisfaction.
Last year I let go a client of over 22 years who's demands that my furniture and location in that salon, to accommodate her new weight, could not be met. She had been increasing angry about a world that did not fit her size and she became angry with me and addressed the situation as prejudice against very large women, even after I explained that the chair was the largest and sturdiest we could find (I dragged the poor salon owner all over town to find it when we set up, considering four very large clients) and there was no place for me to work downstairs. It was her anger and the impression I had that she was looking for a "test case", not her weight, that caused me to suggest she find a salon with no stairs. It was a disappointing conclusion to many years of accommodating her health and needs.