If you're going through the Apple network or using corporate equipment then of course they can universally ban it. They monitor all outbound traffic and audit what you're doing on your computer.
Do you actually think companies just give you root access and unrestricted internet and operate on a "we trust you" model ?
Of course not. My point is not about _how_ companies ban it, or how their IT security policies work, but rather that I think they need to offer an approved, internal alternative. Employees are clearly clamoring to use this type of technology and increasingly see it as necessary for their work. Trying to ban something without an alternative in place (or with draconian "we'll fire you if you try to use it" policies) is where you start to run into trouble.
Do you actually think companies just give you root access and unrestricted internet and operate on a "we trust you" model ?