An anonymous reader writes: The Maryland Court of Special Appeals on Wednesday upheld a historic decision by a state trial court that the warrantless use of cell-site simulators, or Stingrays, violates the Fourth Amendment. The trial had suppressed evidence obtained by the warrantless use of a Stingray -- the first time any court in the nation had done so. Last April, a Baltimore police detective testified that the department has used Stingrays 4,300 times since 2007, usually without notifying judges or defendants. Stingrays mimic cellphone towers, tricking nearby phones into connecting and revealing users' locations. Stingrays sweep up data on every phone nearby -- collecting information on dozens or potentially hundreds of people. The ruling has the potential to set a strong precedent about warrantless location tracking.