Some people are wondering/shocked on why they look like the SS Nazi uniforms.
They DO kind of look like SS uniforms at first, but if you really study them (there's a star on the armbands, not a swastika), they're obviously not. Maybe the costume designer created them unintentionally, or maybe even not. Japan kind of has a thing for Hitler and Nazi designs, trufax. Also, it's quite a common uniform look, so who knows.
I'm sure BoA didn't help to create or have a say in what the back-up dancers would wear anyway.