Personal vs Corporate Device
Even if your company will allow you to plug in your personal device, i'm not sure i would want to have restrictive policies downloaded onto my own device. Also, as a private individual there are sites i may go to that could be at odds with the ethos of my company. I might for example be a regular contributor to anti-globalisation sites. I might even be using a device belonging to one of my company's competitors. Finally, I don't like the idea that personal content might be subject to corporate scrutiny - which should be the case if a company wishes to protect its corporate image as represented by its employees.