Drawings as pegs

Hi,
I’m going back through the Toon Boom Animate Pro Tutorials,
to improve my skills.
When I watched the Articulation videos last year,
I thought it recommended using drawing layers as pegs,
so that you can transform the parent with out affecting
the children. But as I watch them now, I don’t see any mention
of that. Did I misunderstand that last time, or was that a
school of thought that was since changed?
Thanx,
Justin