I daresay it would look quite nice if loosely tied. I'm trying to visualise how they'd get bent corners from being tied like a parcel...
I have found some wonderful, 3-card-spread-sized dupion silk little reading cloths from India (30 cm square). Perfect size. Fold them in half, put deck in middle, flap fabric over either side and put in bag. Doesn't take up too much volume (with so many bags, deck and spreadcloth don't fit easily) and is nicely protected.
I've bought 7 or 8 in different colours now (no distracting patterns; plain only) and love them. Perfect size for reading on the hoof and added protection in bag.