Yeah, we average about one staff member a year attacked with pointy bladey things while on home visits, ranging from kitchen knives to samurai swords. Actually, neither would impact the phone in my coat pocket. And oddly, the clients often calm down and ring the police themselves once they see the red stuff... not even stopping to rifle pockets.

Of course, it's supposed to be Risk Assessed. But our security guys actually recommend using the ICE system in your phone.