Legal and staffing challenges have made it nearly impossible to enforce the 2010 law, leaving commercial operators of multiple short-term units able to continue skirting it. That’s where the bill, introduced by Councilman Ben Kallos, comes in. The bill requires hosts to register with the city and obtain a registration number before they can rent out their homes, and only short-term rentals that conform to city and state law are eligible: the unit must be the host’s primary residence, and the host must be present during the rental. Registration will make it more difficult for landlords and other scofflaw operators to maintain multiple listings that are not their primary residence.