This might have been the push I needed to finally try this out in my guest bedroom!
Putting a curtain to hide clutter is smart if the shelves are used for storage vs. Display. I wouldn't "puddle" the curtains because it adds visual clutter and simply is not necessary. If foot traffic is high in that area then the curtains will get and look filthy bunched up on the floor. If you are using the shelving for display only, then I find the curtain pulled aside looks weird.
