Flipping can be as simple as having them read a chapter before coming to class to discuss. Just as in any class, you will have students who arrive unprepared (technology or not). They key is to not let these folks become disruptive (nor put them down in front of their peers). Maybe a short assessment where you can personally tell who came prepared, and then an active learning exercise where the unprepared can participate and "catch up." In this way you reward those who came prepared, and take points off (without shaming) the ones who didn't.
