The split-pants or open crouch pant phenomenon is called "kaidangku" in Chinese ( literally "open-crotch pants) and one sees babies, toddlers and young children wearing them everywhere in China and relieving themselves on streets and every place imaginable.
I had read about it, but it took our 12 year old by surprise a little the first day at her Mandarin school when they took the preschoolers out to play at the park. As someone who has been traveling the world non-stop most of her life (constantly these last 7 years), no new cultural thing shocks her too much at this point, she is ever adaptable, so she took it all in stride as she watched (in some fascination) as both boys and girls urinated and defecated outside as needed.
Unlike her mother, our daughter Mozart has already long ago adapted to squat toilets ...from Europe, her Mandarin school in Penang and else where (and they only had squat toilets at this Mandarin school in Beijing where she lived for a month). I will soon write a post with tips for squat toilets for older folks like me who can't squat (thanks to my mobility challenges).
Being diaper free and elimination communication has been used for centuries in many countries besides China, but is gaining in popularity in some parts of the USA. Some feel like it is better for the environment and the family.