They act a little snippy about extra tape on the boxes. so I get around that easily. I simply GLUE the bottom box lids together, then when closing it I put in a layer of plastic wrap (if I haven't already put the contents in a plastic bag) and then put dabs of Elmer's Glue on the top and put a heavy weight on it till dry. No way will that box come apart short of being sliced open!!
Of course I ALWAYS put wide plastic over the label, and an extra label taped to the inside contents.