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?
The manual release still has to function, that's not in question. The question is being able to release it quickly in the event that the garage door sensors fail in such a way that results in crush injuries.
Since we all carry pocket knives (right?!?) the simplest solution is to back the spring with a piece of cord and cut through it if required. Zip ties are a PITA to cut with knives.
Personally, I'd use an
autolocking biner and cord loop. Easy to open by hand, but impossible with just a coat hanger hook.