Where OS's are heading.

From:

Steve Jobs Didn’t Believe in Macs for Business. But Here They Are
 http://www.wired.com/wiredenterprise/2012/02/mokafive-steve-jobs/

MokaFive runs Windows in what it calls a secure container on Mac OS X and backs up work onto a company’s servers. IT managers can create a common Windows image that they can then push down to an employee’s Mac over the network. They can also update the image over the network, but that virtualized Windows desktop still works when the machine is offline.

Managers can also prevent employees from moving data out of their virtualized Windows desktop, and when data is moved over the network, it’s encrypted. But Gartner’s Cosgrove questions whether the tool is suited for that are handling extremely sensitive data, such as healthcare outfits and government agencies. “[Client-side virtualization tools] tend to be [used] in areas with low security,” he tells Wired.

There are already system deployed in top secret facilities where it's limited to physical access and your eye's only.  Their are people who work all day on system where nothing can be sent or downloaded.