The ordinance caps the units per building that can be used as vacation rentals, which restricts the rights of other people in the building to use their homes as they see fit, Huebert said. Additionally, homeowners can only get vacation rental licenses if they are renting out their primary residence, barring a few exceptions, which the suit says discriminates against non-Illinois dwellers. The primary residence restriction applies to people in single-family homes and two- to four-unit buildings.