I’d venture that you won’t see it outside of Chen. The mechanics of Chen require the figure eight patern with the knees as a result of the spirals inherent in practicing chan ssu jin, so applying these same patterns in tui shou is a natural extension of your solo practice. You won’t find similar leg work in either Yang or Wu, at least none of the Yang and wu stylists I’ve ever seen.
Yes, we’ve been known to do that (yang style), but I wouldn’t say it’s a major thing, or something we do a lot. It’s probably much more frequently used in Chen style, from what people have said.
In my time training Yang’s, we did lots of chan-ssu-chin with the legs and as much chi-gurk (sticky legs) as any other type of isolated training drill. They were actually the first things I was shown for applying TCC’s rotation and extension principles. It only made good sense…