I have a similar story, people are weird.
I was in Joe and the Juice last Christmas, the one behind selfridges so super busy and this girl was in with her friends. She was dressed in this gorgeous cream outfit and she had come on her period. I noticed as I was sat down and her bum was at my eyeline at the till. I went and told her discreetly and she thanked me and put her scarf around her bum.
Her friends asked her what I said and when she told them they checked and said there was no stains (there absolutely was
) and that I was lying. She took the scarf off and walked past me and called me a weirdo.
I felt a bit sorry for her but also delighted that her karma was going to be walking around Oxford st like that and hoped to
duck she regretted calling me a weirdo when she finally went toilet and saw.