The BlackBerry smartphones are not tied to BIS/BES because you can subscribe to a non-BlackBerry data plan though you loose the exceptionally efficient data compression and will experience data usage akin to say the Apple iPad. There is no requirement that a BlackBerry smartphone have any data plan though anything outside of telephone calls, SMS and maybe MMS will not be available. You can have a BlackBerry smartphone without a voice plan but have a BIS/BES data plan, or you can have a voice plan without any data plan.