I mean "must" obviously doesn't count in this situation though, because they didn't do that thing and yet still got the money.
I'm wondering if maybe there's a fraud situation where someone figured out how to GPS spoof their app, create a fake identity, and is literally sitting there in some remote country faking deliveries for a day until they get caught and disabled but still running away with the money in the meantime?
I don't know enough about how the supply side of Instacart works to game through the scam here, but there's clearly a scam here because they DID accept my order, I did get charged (and later refunded), and they did provide a streetview photo of the house as their "proof".