I've been thinking about fair lately. I have always done my best to make my class fair. However flipping extends the classroom into the home and the home is not fair for all students. The availability of internet or computers is not the same for all students. Time at home is also not fair. Many students take care of siblings or work jobs at night. Imagine the stress placed on a family with no internet access. Imagine working a second job and then having to drive your kid to the library so they could complete a science assignment.
The only thing that is fair for all students is the classroom.
We need to stop talking about the flipped classroom and start talking about the learning classroom. The most compelling element of this movement is not the video podcasts, it is the mastery system of learning in the classroom.