Some people never progress beyond the falling leaf. They learn the falling leaf on the healside which teaches them heal edge control. They weren't forced to do the same falling leaf on toe-side.
The toe side is typically the more uncomfortable edge to learn. Your back is to the fall line.
With no toe side comfort the occasional snowboarder only turns on their heal edge or will do the "turbo leaf" bombing down a steep run on nothing but their heal edge.
Sad to watch as they scrape all of the snow off the good runs!