“Flipping of the classroom” is both and intriguing and disruptive idea, but there will be a host of problems, perhaps “confounding factors” is better, in its implementation. Andrew points out an obvious one:
1. This requires technology that many students (even in the richest nation) are not able to access.
This problem should be addressed, and it is a shame that it has not been addressed. For example, South Korea has committed to making a fast internet available to all of its citizens in the near future. The US needs to realize that technological advancement is one of the main paths to economic expansion, but sadly fails to do so. As a result, this problem may motivate positive action on the part of countries to provide technological progress which will likely lead to economic expansion and a higher standard of living for its citizens.

However, there are other problems as well:

2. Students must be sufficiently disciplined to sit for a relatively lengthy period on a regular basis
The sad fact is that most students in the US would not be able to complete a program as described by Sal Khan. The high achieving students, those in AP courses and those that Khan describes as his cousins, will be wildly successful in this model. However, the typical American student who is perpetually asking: “why do I need to learn this?” will fail miserably under this method. Facebook, video games, etc. will leech the attention of these students away from their studies and leave them chronically unprepared for the flipped classroom. This is not Mr. Khan’s fault, but it is the reality of the US student

3. Students must be self-directed learners
Sadly, most students will not be successful on their own because few will study or learn material because most students are not able to manage their free time, energy, etc. Those who are able to do this will be wildly successful, and this is probably a good thing for work life or for later on in life. So while it is a challenge, it will likely differentiate the better candidates for success in a more predictable and logical manner.

5. Students will need a support system
What these, indeed all, students need are effective parents who construct a support system to overcome the challenges of a Facebook, texting, video game world. Some parents will rise to this challenge, but many will fail. A main driver of success here will be resources available to parents to construct and manage a support system for their child. Most parents in the US are working, at least one job, and have a myriad of responsibilities both inside and outside the house. Combine this with a structurally contracting economy, and it seems unlikely that many parents will be able to multitask appropriately to provide this support system.

6. Students will need to be re-categorized
Discipline and focus will be the two most prized resources once this disruptive technology takes hold. Students lacking discipline and focus will flounder since there is nothing similar to social promotion within the “flipped classroom” constructs. Students who are disciplined will fly through schooling, and likely into satisfying, emotionally and financially, careers. Those who lack these abilities will be perpetually tardy and unprepared.

If you stuck around to this point, you have probably figured out that I see this model as presenting worthy challenges to any society. However, it will exacerbate the challenges faced by most students in the US, and it is likely to lead to many, many students in the US coming up short in secondary school.

Tl;dr – this is a transformative and worthy model, but one that will highlight many negatives about the US that we as a society are loath to address.