Orin Kerr writes:
… As a matter of policy, when should targets of digital evidence investigations receive notice of the court orders? And when and how should they be allowed to challenge the orders as unlawful? In a traditional criminal case, suspects don’t receive notice that they are subjects of monitoring. When the government decides to “tail” a suspect around town, they don’t send them a letter letting them know. Suspects receive notice only in specific contexts, such as if their home is searched pursuant to a warrant. And they have to wait to bring challenges until late in the game. In the case of a warrant, for example, the defendant challenge the warrant until after it has been executed. The question is, if you were writing the statutory network surveillance laws, when would you impose a statutory notice requirement and when would you allow challenges to be brought? Would you try to match overall amount of notice in digital investigations to that of traditional physical investigations? Or would you aim for more or less notice in the electronic setting than in the physical setting? Would you allow challenges to surveillance practices as they were ongoing, or would you require challenges to wait until the order had been executed?
Read more on The Volokh Conspiracy.