Typically, in seeking these records, the government recites all the ways the records might be disguised on a computer and says it must examine all records to find the ones pertaining to its investigation.

The 9th Circuit says:

We accept the reality that such over-seizing is an inherent part of the electronic search process and proceed on the assumption that, when it comes to the seizure of electronic records, this will be far more common than in the days of paper records. This calls for greater vigilance on the part of judicial officers in striking the right balance between the government’s interest in law enforcement and the right of individuals to be free from unreasonable searches and seizures. The process of segregating electronic data that is seizable from that which is not must not become a vehicle for the government to gain access to data which it has no probable cause to collect.

The guidelines to be used in future cases:

1. Magistrates should insist that the government waive reliance upon the plain view doctrine in digital evidence cases. See p. 11876 supra.

2. Segregation and redaction must be either done by specialized personnel or an independent third party. See pp.11880-81 supra. If the segregation is to be done by government computer personnel, it must agree in the warrant application that the computer personnel will not disclose to the investigators any information other than that which is the target of the warrant.

3. Warrants and subpoenas must disclose the actual risks of destruction of information as well as prior efforts to seize that information in other judicial fora. See pp. 11877-78, 11886-87 supra.

4. The government’s search protocol must be designed to uncover only the information for which it has probable cause, and only that information may be examined by the case agents. See pp. 11878, 11880-81 supra.

5. The government must destroy or, if the recipient may lawfully possess it, return non-responsive data, keeping the issuing magistrate informed about when it has done so and what it has kept. See p. 11881-82 supra.

....we trust that the procedures we have outlined above will prove a useful tool for the future. In the end, however, we must rely on the good sense and vigilance of our magistrate judges, who are in the front line of preserving the constitutional freedoms of our citizens while assisting the government in its legitimate efforts to prosecute criminal activity. Nothing we could say would substitute for the sound judgment that judicial officers must exercise in striking this delicate balance.

What is the effect of the opinion?

The decision is a victory for the players' union, which argued for years to have the results destroyed and is still fighting leaks from the material, which was supposed to be anonymous and later was sealed by the courts.

"This was an obvious case of deliberate overreaching by the government in an effort to seize data as to which it lacked probable cause," Chief Judge Alex Kozinski wrote in the 9-2 decision of the 9th U.S. Circuit Court of Appeals.

Barring a last-ditch appeal to the U.S. Supreme Court, the test results and samples will be destroyed, and prosecutors cannot use the information. Union lawyers said the government returned the evidence shortly after earlier trial court rulings.