Oracle text of a basic land?
I have received this question twice. The first situation was as we were walking away from the table so he could discreetly make a slow play complaint. The second was for Wastes to see if it was affected by Blood Moon or was a type that could be chosen by Sundering Titan.
If someone asked me for the oracle text to Mountain, I would recite it from memory quickly. I don't know why they would be asking that question, but I would expect to figure it out in the next few seconds if there's an underlying reason (can I speak with you away from the table) or if they're trying to potentially stall (can we have a time extension).
As for the situation you described, I personally am not comfortable with using a judge as a prop for a bluff. I would ask him what the name of the card is. Although I'd try to pick up how jokingly the question is asked and maybe respond sarcastically as well just based on the feel at the table.