San Francisco Supervisors today approved legislation that requires short term rental platforms like Airbnb to list only rentals that have undergone the required registration process with the city.

The legislation places the onus on Airbnb, HomeAway and other hosting platforms to make sure hosts who want to rent out part of their homes to visitors have gotten a business license from the city. Supervisor David Campos, who put forward the law together with Supervisor Aaron Peskin, called the shift in responsibility a move toward “corporate responsibility.”

The Board of Supervisors Government Audit and Oversight committee unanimously supported the measure last week. On Tuesday, it won unanimous support from 10 supervisors, (with Supervisor Mark Farrell recusing himself due to a conflict of interest) which secures it from a mayoral veto.

In late 2014, the city approved legislation to require residents renting their spare rooms through home sharing platforms to get a business license and registration number along with paying hotel taxes. That law went into effect in February 2015.

Tenant advocates and other critics worry that unregulated short term rentals incentivize landlords to remove units from the rental market and put them on sites like Airbnb full-time – a practice made illegal by the 2014 legislation, which required that short term rentals only occur in a host’s primary residence.

But critics have maintained that the law was unenforceable, since the newly created Office of Short Term Rentals’ enforcement is complaint-based and does not know which addresses are rented. A Budget and Legislative Analyst’s report found that more than 75 percent of short term rentals in the city are likely not registered.

Under the new law, the hosting platforms themselves can face fines of up to $1,000 a day for listing unregistered short term rentals.

Supervisor Scott Wiener also supported the measure, but made a point of repeating his stance that the previous legislation was not given enough time to become effective, and noted again a recent uptick in registrations.

Opponents of the newly passed legislation have warned that it may open the city to a lawsuit from Airbnb over a law that protects online distributors from punishment for user-produced content, though a city attorney questioned on the topic by Campos at the committee meeting indicated confidence that the legislation would not be problematic in that sense.

Critics also say the new approach will force platforms to police their own users, which they say is the responsibility of the government.