@AdamNichol you need to get your story right, she was told to cover up by the greeting staff when she stepped onto the plane, she said I am happy to do that (she clearly wasn't) and asked them to show her where it stipulates this in their policy. Then continued to her seat and didn't cover up.
It doesn't matter what she wore when she checked in, went through security etc because she had a jacket with her and we only have her word that she wasn't wearing it in the airport.
The reason the woman on the sofa on TM tried to turn her around was so you could see how little material there was in the back of the top.
It does raise an interesting debate though, is this an okay outfit because of the destination? Or is this a your child's secondary school teacher could of course wear it being an NQT at 22, or in an office? I wonder if she could wear that to work?
And you'll find LOTS of airlines have dress code policies for their passengers.