The company had already promised close reviews of high-risk rentals, such as people renting giant homes when they live in the area. The Halloween shooting occurred at an estate that was ostensibly rented for a family gathering, but was really used to host a party with more than 100 guests.
To back up the review process, Airbnb will also implement a "guest guarantee" if your rental doesn't match the description. You'll either get an alternative that's worth at least as much as what you paid or, if that isn't available, a full refund.
As with the policy changes unveiled in the immediate aftermath of the shooting, there's a degree of damage control involved. Airbnb doesn't want would-be customers to believe that violence or scams are relatively commonplace. This could root out misleading entries that would otherwise go unnoticed, though. If there's a concern, it's whether or not there will be ongoing reviews. Homeowners and rentals change, and a one-time review might not help if new shady rentals go unreported.