DOT May 8, 2015 Notice: Enforcement Policy Regarding Mistaken Fares
A notice was posted sometime yesterday on the DOT website under What's new regarding the enforcement of mistake fares. It is silent on the 24 hour hold issue, but after a quick read, it seems to be a temporary "get out of jail free card" for the airlines going forward from Friday.
https://cms.dot.gov/sites/dot.gov/fi...t_05082015.pdf