A number of laws govern information gathering, or surveillance, by private parties in the physical world. But we lack a compelling theory of privacy harm that accounts for the state\u27s interest in enacting these laws. Without a theory of privacy harm, these laws will be enacted piecemeal. Legislators will have a difficult time justifying the laws to constituents; the laws will not be adequately tailored to legislative interest; and courts will find it challenging to weigh privacy harms against other strong values, such as freedom of expression. This Article identifies the government interest in enacting laws governing surveillance by private parties. Using social psychologist Irwin Altman\u27s framework of boundary management as a jumpi...