Yonus bin Muhammad bin Muslim يونس بن محمد بن مسلم المؤدب · The Chapters on Business Transactions

"When you come to a shepherd, call him three times. If he answers (all well and good), otherwise drink (milk from the flock) without taking advantage. And when you come to a garden call the owner of the garden three times. If he answers (all well and good), otherwise eat (from the produce of the garden) without taking advantage."