Correction: The 12th paragraph of this story has been revised to more accurately reflect eBay’s argument relative to the Supreme Court’s Inwood decision.

It isn’t often that nearly every seat is full in the 2nd U.S. Circuit Court of Appeals’ ample countroom. That it was on Thursday morning during oral arguments in the Tiffany v. eBay appeal indicates just how high the stakes are in this trademark infringement case — not just for the parties directly involved, but for anyone with a vested interest on either side of the key issues being litigated.