Well, eBay is not going to like this but their “guaranteed delivery” is a fiction. Once a package is turned over to the post office what happens to it then is beyond anyone’s control - including eBay. Further, if there are any delays caused by any weather or mechanical interruptions that is beyond even the control of the post office, let alone eBay.
“Guaranteed delivery” is nothing more than an advertising gimmick. They are betting that the vast majority of packages will be delivered according to the Guesstimated delivery time so that they can just shrug off the very few that might run late. They just point the finger at the post office and say “Oops”.
Think about it - how in the world can eBay (or anybody for that matter) guarantee the actions of an organization over which they have no control (the post office) when the post office itself has no control over the airplanes that actually move the mail when the airlines themselves have no control over the weather that can ground the planes and stop the mail.
"Laissez-faire capitalism (AKA The Great Material Continuum) is the only social system based on the recognition of individual rights and, therefore, the only system that bans force from social relationships." ~ Ayn Rand
