I have done this but had a problem as my phone wouldn't allow multiple contact listings with the same number. Simple solution: add +44 to the front of the number (UK only), does the same but the phone sees it as a different number. Another tip, if the ICE number you add calls a relative at work make sure you add their real name so the friendly paramedic can ask for them. I have now got 4 ICE numbers in my phone, first to to ring my wife at work then her cell phone then our home phone then if all else fails my parents.