This is basically an excuse to justify sending an open box. The box is going to be open (and problably it won't even be the original Nokia box) because these N900s are actually refurbished or fake.

Another thing they do to justify this and not tip unsuspecting buyers is "include presents" in the box. These companies (mostly Chinese) make a lot of money fraudulently selling as new devices which just aren't. I think eBay should crack down on them but they won't because eBay just cares about making money.