Years ago, I worked in a very sensitive area.I work for a defense contractor and they don't allow camera phones. Would you guys sneak your iPhone into work because you pay soo much for the monthly service cost?
If you had any unauthorized electronic equipment, the government would confiscate it on the spot and you faced disciplinary action. It did not matter how much the electronic device cost you, it became government property.
I would suggest that you do not risk loosing your job over something as simple as a cell phone.