Rambam, Laws of Hiring 9:4

If an employer hires workers and they mislead the employer, or he misleads them, they have no claim against each other except for taromet [a non-monetary remedy, similar to nominal damages]. In what circumstances? If the work has not yet begun. But if donkey drivers go [to the appointed place] and find no produce, or workers find the field wet [which makes it impossible to harvest a field], or a worker hired to water a field finds it already flooded — if the employer had already visited [the work site] the previous evening and decided the workers were required — the workers have no remedy, since what could the employer have done? But if the employer did not visit, he must pay them “idle wage” (since a person who comes loaded is not the same as a person who comes empty and wastes time). In what circumstances? When the workers have not yet begun to work. But if the worker begins to work and then changes his mind, he may do so, even if he has only worked half the day, as it says: “For it is to me [God] that the Israelites are slaves,” (Leviticus 25:42) – they are slaves to Me, not slaves to other slaves. [Ziegler translation]