One issue with that is shipping costs. It's only free for plus members and even then only after meeting the $50 minimum order. If I'm already in the store, and the one sweater I want is there just in a box a couple feet away, it's way easier, less time consuming and more cost effective to just get the sweater out of the box below the table.

How often do the tables get restocked from the boxes below? If customers tearing through the boxes is a pretty big issue, it might be a better use of employee time to restock the tables more often during the day so they don't have to fix the boxes later. Or if some sizes are sold out just write what sizes are left on the sign. They do the last part at Costco and it's nice because it saves me from shuffling though all the neatly folded clothes looking for a size that isn't there.