At anytime a judge could order your information and put a secret gag order. A valid concern. The government seizes domains they deem possible copyright infringement. One judge order could open the floodgates.
For a judge to issue a warrant, a prosecutor or cop has to swear that they have probable cause to believe that you've committed a specific crime. Judges can't just write warrants arbitrarily. (Of course, this process can be abused, but it's still pretty far from a judge being able to authorize pulling the data of random people.)
The Fourth Amendment says: "... no Warrants shall issue, but upon probable cause, supported by Oath or affirmation, and particularly describing the place to be searched, and the persons or things to be seized."
