For an example of how difficult it is to corral customer behavior, consider one librarian’s account of reopening her public library in Florida. Once inside the building, many patrons took off or pulled down their masks. Despite instructions to the contrary, visitors would crowd next to each other near the chairs or at the computers, including at computers that were explicitly designated as not working. The staff, already tasked with extra responsibilities, rapidly became exhausted. And of course, trying to enforce the rules brought them into closer contact with the patrons, creating yet further sources of risk.