This case, otherwise known as the Peaches’ House Party Case, deals with probable cause and qualified immunity of police officers. Justice Thomas wrote the opinion for a unanimous court overturning judgments of almost $1,000,000 awarded to partygoers for what the lower court found to be their unlawful arrest. Turns out, the plaintiffs had entered an unoccupied house and, well, had a party. When neighbors complained and the police showed up, some of the partygoers were arrested.
The case itself: D.C. v. Wesby (2018)
From The Volokh Conspiracy on Reason.com: Imagining a World Without Qualified Immunity, Part I
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