Ive noticed that the moment a seller generates a shipping label with a tracking number, that an email is sent, stating that an item has been shipped. This is actually not the case many times. The issuance of a USPS tracking number is often what has occurred, only, at that time.
For example, a label w/ a tracking # could be printed today, but not actually be mailed by the seller until next Thurs; the ebay system, however, will notify a buyer that his/her item has "shipped" today.
Not the best set up but I guess it's better than nothing at all.
