It is not an "emergency" feature at all. It is there in case the door opener fails so you can open it up like people did before there were garage door openers.
If the sensors that are supposed to detect obstructions, like your child, fails, how are you supposed to prevent the door from squashing your child? Google "garage door crushes" and you'll find any number of examples of people being injured or even killed when a closing garage door sensor failed to reverse (even adults). If the motor or mechanism gets jammed by the obstruction that is being crushed, how else can you lift the door if there isn't a release?
Short of busting a window in your garage door or making a hole in it, I don't see how you can get the coat hanger to the release latch.
There are any number of videos demonstrating the technique, like
this one.
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