I seem to recall questions being asked. We did have some lecturers whose English wasn't good enough to rephrase what they had said - they just repeated what they had already said like a rewound recording. It was not helpful and I can't see rewinding a video to be helpful either. Also if I don't understand something at the beginning and therefore can't follow the next step I need to get an answer now not tomorrow.
Yet Khan's niece Nadia preferred his videos to live tutoring sessions because she could watch them multiple times and go at her own pace. There may certainly be times when most of a video lecture is ineffective during the first viewing because of a question that pops up at the start. On the other hand, there are times when most of a live lecture is ineffective because it goes in real-time and a student didn't even have time to reflect on what they may have misunderstood in the first part, and formulate an appropriate question. Sometimes a single sentence perfectly communicates an idea, but the concept isn't understood until the student has time to reflect on it. Videos give students that time.
Finally why go to a class to do busywork slowly with a bunch of people who probably haven't done the prep work and will ask the same questions over and over again or expect you to do their work for you?
As I've seen this implemented, the teachers know if the students played the videos or not. So the teachers can make a judgement call about helping the kids who didn't view them or answering questions for those that did. Unless you're waiting for a question to be answered, there's no reason to proceed slowly. I don't know why you are implying that some students will expect others to do their work for them, or how that would be specific to flipped classrooms.
