You had to worry about the people who weren't in the cave, which was the audience we actually wanted, which was much larger."

Perhaps it would have been more apt to call them an island. You might make it easier for the cruise ship tourists to collect your game if you drop it in the ocean, and some people on the island might swim out to it if it's not too far, but if you drop it far enough (like on the mainland), the people on the island won't be bothered to go for it and the people on the mainland won't care.