Here’s The Reason Singaporean Girl Group By2 Has Been Posing This Way For 11 Years
There's actually a lot of thought that was put into it.

But they’re not the first ones to notice this. Back in 2012, the judges of Chinese reality show, Shake It Up, have commented on the duo’s pose before. Turns out, the sisters are covering up a flaw.
“Actually, our legs aren’t straight, unlike normal people. So we’d cross them to hide it,” Miko and Yumi explained. The host then joked “They had covered their flaws so well but you pointed it out just like that.”
Singaporean pop group By2 recently had their second shot at fame when they participated in the third season of Chinese talent show, The Coming One, which gives artistes a chance to make a comeback.