I'm not sure if this is entirely true or something I've dreamed up but I've got it at the back of my head that if you share a container, both you and the other party have to be present when the container is opened? So if the other person isn't due to arrive for another 3 months then you have to wait for them before you get your stuff. I've a horrible feeling it was a crock of sh*t designed to make us take a sole container!