The Airtel&#x2F;Docomo analogy has been played out in the US. ATT Wireless calls to other ATT Wireless subscribers are considered mobile-to-mobile and don&#x27;t count towards the minutes limit. Same for the rest of the major carriers, so families who chat a lot frequently pick carriers strategically (the balkanization you&#x27;re describing).<p>Overall, it has not caused any major disasters.