Yep. Old trick. I thought all the older users did it.Trick I learned when I first strted with P4.  It is also the easy/ quick way to do clothes you model. That's all these developement Cr2 are.  Clothes you can cut down the size of the Cr2 by deleting the groups you don't need. Though it's wise to leave one bone extra to what you have in groups.

example. boot goes as far as the shin. You keep want the thigh included in the Cr2. A short sleeve stops at the shoulder. You want to include the forarm as well in the Cr2.