Rather one should ask "Would you be able to answer any question and fulfill any request about the Grand Canyon given to you by others in a way that will be indistinguishable from someone who has been to the Grand Canyon"
You might equally contrast someone who is physically in the Grand Canyon with an LLM given access to a drone with sensory attachments. I'd bet that if you told groups of humans and drone-controlling AIs to find something interesting, the humans would be more variable and cover a wider range of interesting discoveries but often just give up on the task, while the AI would be more likely to find something but would cluster around certain discoveries and make fewer overall.
I'd be fantastically surprised if you could provide a precise answer to any such question without extensive security footage that doesn't exist.
An estimate, perhaps, but you probably couldn't even answer a simpler "how many people are currently in the canyon" without resorting to estimation given the lack of information currently available via the mentioned sources.