Presumably because they mean the tins themselves, empty of tobacco? I assume a declaration of tobacco itself is covered elsewhere? Smells like Latakia to me.I see it as debating whether this behavior is legal or not. In my case, I only ship vintage tobacco. And noone so far could give me a solid explanation at which age a tin stops being taxable tobacco and starts being a collectible item.
When the content can no longer be smoked? That would be kind of Schrödinger's cat.