As it happens, the relevant case law is New York Times Co vs. Sullivan. According to that case, libel liability still applies when the information published is both untrue, and was published "with reckless disregard of whether it was false or not."

In other words, a policy of publishing without investigation would not limit libel liability. If the information is false, and the publishers did not have a good-faith belief that it is true, then they might still be held liable.