So, this seemed kind of like a thing in China. Dressing alike, I mean.
As you can tell from my second photo of the lady and her mini-me, people generally find it way more pleasant to be photographed from behind without their knowledge. And also, as a white woman in China, one must remind oneself that it's kind of tricky to blend in. Sort of like being a black man in Copenhagen, I would imagine.
FYI though, I gave her a neat little wave afterward and mouthed "oh my god, so cute" in the kid's direction after taking the photo. And I kind of sensed it was all good and that neither of them felt bad and objectified.