Yes I am. I know iOS allows someone to dial their emergency contact from a locked phone, so in that case I will receive a call from the person's phone that I know about. Otherwise, they leave a message and I get to it immediately and call them back.
The reality of an emergency situation where someone I know has me listed as an ICE contact and someone else calls on their behalf from an unknown number is that I cannot do much to help them in a situation that a minute or two of phone-tag would introduce. That's what 911 and other emergency services are for. If you are ever in a situation where you come across someone that has just sustained major injury, who are you going to call first? Their children or spouse to let them know of the situation, or medical help via 911? I'd hope you would chose the latter to get them the critical medical help they need before you inform someone else of the situation.
