Special Cases of Unsolicited Benefits

A secretary took it upon herself to decorate her office, and installed some of her own paintings on the walls. When her boss sees it, he says he doesn’t like them and, therefore, won’t pay her for the full price. Instead, he says that he will pay cost-price for her paintings. She’s insulted and says she’ll just take them back. However, he doesn’t want it removed because he is worried that doing so will ruin the walls. What is the halacha in this case?

A contractor is building a home and decides on his own to install outdoor lighting to beautify the house at night. The homeowner says that he didn’t need those lights and that he won’t pay for them. A few weeks later, the contractor notes that those lights are turned on and used every night. Since the homeowner is deriving benefit from them, can the contractor come back to him and demand payment?

Reuven pays a lot of money to fly in a famous singer to perform at his simcha . Shimon hears that this singer is coming to town and hires him to sing at his simcha as well. Reuven says that Shimon should pay for half of the plane ticket and related expenses because he is benefiting from having the singer in town. Is he correct?

Reuven asks Shimon, a business professional, to join him for lunch in a restaurant in order to ask him some business-related questions. When the bill comes, Shimon expects Reuven to pay for his meal; however, it soon became clear that Shimon was not planning on doing so. Can Shimon tell Reuven that he should pay?