Tim and Tom are twins. They live and work near the beach and are also partners in TnT, Inc., a bicycle messenger service. When deliveries are few, especially in the summer, Tom without telling Tim, rents the extra bicycles to tourists who want to explore the resort area. Because the bicycles aren't being used for deliveries, is it acceptable for Tom to keep the proceeds he receives from renting leasing the unused bicycles? Explain your answer based on the facts in the scenario in the context of partnership law.