Airbnb is doing major damage control after a mass shooting in a home rented on its site and a widely read report on Airbnb hosts defrauding customers.

In what CEO Brian Chesky called “the most significant change to our platform” to date, Airbnb will verify all its hosts, manually vet “high-risk” bookings and ensure that customers at least get a 100% refund if the homes they book fall short of what the listings promised.

These appear to be meaningful steps that could help customers trust Airbnb more. Exactly how to implement these changes—and how much they will cost—seems to be a work in progress. Chesky said at the New York Times’ DealBook conference Wednesday that some of the details are still being worked out.

In particular, it will be important to know exactly how the company is verifying its more than seven million listings. Will that have an impact on growth—and how easily will people be able to add their homes for rent to the website?

Another question is why it took Airbnb so long. The shooting in Orinda, Calif., on Halloween certainly wasn’t the first death in an Airbnb home. As Vice reported last week, rampant fraud on Airbnb’s site has been a longstanding issue for the company. 

Chesky badly wants Airbnb to be seen as a force for good in the world. He appears to be challenging the company to make major changes to how the platform functions as the company prepares to go public sometime next year. But a real test of his leadership will be whether the company tackles its future problems proactively, rather than waiting for a swell of bad press.