During Yami Yugi first Duel, one of the operators notified Kaiba that Yami's opponents cards had not been registered. Seto Kaiba asked if they were God cards and she replied that they were not and that they were counterfeit.
Kaiba was trying to locate Yami Yugi after his Duel Disk had disappeared from their tracking system. Kaiba suspected he must have went into a basement, which would have caused the signal to disconnect and that if Yami was Dueling, it must be on a different system. He asked the operators to search for all Duel Rings in Domino City that are compatible with Duel Disks. Two of them replied with "understood!". Once they found all such systems, Kaiba asked them to narrow the results down to ones that are not connected to the main computer and have a basement that blocks all signals. That left a single location.
In the Japanese ending credits, Mika Ishibashi is credited as operator (オペレーター operētā) for the single syllable of dialogue はっ (ha'), meaning "understood", spoken in unison between two operators.
While searching for Egyptian God cards using the Duel Disk surveillance network, five of the operators reported nothing had been found in Domino City's A, B, C, D, and E blocks respectively. They were supervised by "Engineer A", who then received a call from Seto Kaiba and nervously reported that they had not found the God cards or Rare Hunters.