We flew one-way from Cincinnati to Los Angeles last December-me,DW,DS-12,DD-6,DD-4. Going cross country one-way, we were all searched as well as every bag, both checked and carry on. Our family of five had 10 people searching our bags and the process was pretty smooth. I would not prepare my child for anything more than going through the scanner. Perhaps a trip to a larger museum or a local courthouse where these are in use would be warranted. Remember that your bags will be searched when entering all of the area theme parks. We told our kids to be ready and to ask questions if they needed to.