Chinese etiquette: decline twice; they’re just being polite unless they offer three times.
IIRC, modern Japan* has something very similar to this as their de facto etiquette in such a situation, so I had wondered if that was the case :D I’m delighted to find out my first instinct was correct! It makes the scene so much funnier when you know the underlying etiquette.
Les touristes comme les gens d’affaires aiment se balader dans le jardin Yuyan de Shanghaï, que notre journaliste découvre avec des pros de l’étiquette locale.