On Monday, the Supreme Court declared that law unconstitutional.

The majority opinion was written by Justice Sonia Sotomayor, the high court’s foremost champion of safeguarding privacy rights against aggressive searches and seizures. The 5-to-4 ruling, embraced by the court’s liberal wing, struck down the law because it penalizes people for failing to give up records without affording any opportunity to challenge the lawfulness or reasonableness of the request.

With rare exceptions, for an administrative search to be constitutional, the subject “must be afforded an opportunity to obtain precompliance review before a neutral decision maker,” Sotomayor wrote. “We see no reason why this minimal requirement is inapplicable here.” Although the Court has never specified the form such a review must take, Los Angeles did not even attempt to argue that its law affords hotel operators any opportunity for a challenge, meaning that a hotel owner who refuses access to his or her registry “can be arrested on the spot.”

The law is therefore “facially invalid,” she wrote.

Sotomayor went on to explain why she believes that upholding the law would have been dangerous.

“The ordinance creates an intolerable risk that searches authorized by it will exceed statutory limits, or be used as a pretext to harass hotel operators and their guests,” she explains. “Even if a hotel has been searched 10 times a day, every day, for three months, without any violation being found, the operator can only refuse to comply with an officer’s demand to turn over the registry at his or her own peril.” Now, misbehavior by L.A. or municipalities with similar hotel regulations can be checked before police can coerce innkeepers into granting abusive requests. And police will continue to get cooperation most times from most inns, at least if they treat innkeepers with respect and don’t abuse their authority.

As for inns rife with criminals and complicit innkeepers, police can send an undercover cop with $50 in bribe money to ascertain if the register requirement is easily avoided; or they can go through minimal administrative burdens to see the whole registry, though I don’t see why known criminals wouldn’t use fake names and IDs.

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Justice Antonin Scalia was unmoved by the majority opinion. Writing in a dissent joined by Justices Roberts and Thomas, he declared that inns belong to a special class of heavily regulated industries for which long precedent holds that “when an entrepreneur embarks upon such a business, he has voluntarily chosen to subject himself to a full arsenal of governmental regulation.” At the time of the Founding, “searches—indeed, warrantless searches—of inns and similar places of public accommodation were commonplace,” the conservative jurist observed. “For example, although Massachusetts was perhaps the State most protective against government searches, ‘the state code of 1788 still allowed tithingmen to search public houses of entertainment on every Sabbath without any sort of warrant.’”