A class action complaint filed by artists alleging that Stability, Runway, and DeviantArt improperly trained their AIs on copyrighted paintings can proceed, but only partially, the presiding court said on Monday. In a mixed verdict, some of the plaintiffs' claims were dismissed but others were upheld, implying that the case could go to trial. That's terrible news for AI developers: even if they win, the process will be costly and time-consuming, with a lot of dirty laundry on display. And they are far from the only companies fighting copyright accusations.