To avoid unauthorized parties, Airbnb will stop some U.S. guests under 25-years-old from booking certain homes. Guests younger than 24 with less than three positive reviews will be unable to book entire houses close to their residence. It's unknown what is meant by "close," and those guests will still be able to book houses far away. Guests under 25 with at least three good reviews and no negatives will not be restricted. Airbnb have been screening for "high risk" bookings after a November incident in which five people were shot and killed. The new policy already went into effect in Canada and the company reports a “meaningful drop” in party houses. "We’re taking actions to support safe and responsible travel in the United States,” the company said.