How can they prove he is in contempt of the court? Someone who forgot the password would very well be found in contempt of the court, despite not doing anything

How can they prove he is in contempt of the court? Someone who forgot the password would very well be found in contempt of the court, despite not doing anything wrong. How can you jail someone for being in contempt of the court when there is no proof that he has the password? In fact, it seems dangerous for the judge to be able to jail anyone without a jury verdict. It seems to bypass legal protections.