I think it should be allowed as long as the Kale that goes into the box weighs a minimum of 5 lbs and has not been parted prior to going into the box. This will ensure that cooks don't just take the easy way out and only use the best parts of the Kale. The spirit of the original rule was that garnishing the boxes is to be a long tedious process.
Lets face it taking only the best parts of Kale and using it to make garnishing quicker and easier just ain't BBQ and if they allow that, then it might as well be a grilling contest!!!!!