I don't know. If the policy of the store is that a mask is mandatory, and someone is not wearing a mask, aren't they the person disregarding policy? I'm not sure that the people who ARE following the policy are in the wrong. Given her reaction in the video, I think she simply opted not to wear one.
I can see the "I can't medically wear a mask" going the way of service animals very quickly. I feel badly for those that are genuinely stuck between a rock and a hard place with this, but there are definitely people going this route to prove they can't be FORCED to wear a mask. Meanwhile, if I showed up at a store and said "I have shingles, wearing a shirt is extremely painful for me right now," they probably still wouldn't let me in.