The U.S. Justice Department on Thursday backed consumers who are fighting to revive a closely watched lawsuit accusing major hotels in Las Vegas of using shared data and computer algorithms to charge artificially inflated room rates.

Justice Department lawyers said in a friend-of-the-court brief to the 9th U.S. Circuit Court of Appeals that the use of algorithms by competitors to guide pricing decisions created “new dangers” for consumers.

The DOJ said a federal judge in Nevada who dismissed the consumers’ proposed class action made legal errors that should not be upheld.