Safety Knot?

I’m uncertain about its safety… yet I’ve used it and found no issues. I read this somewhere else… location unclear… but decided to share it here for everyone’s consideration. The method involves pulling only part of the rope tail through the knot’s final stage, creating a loop while leaving a free end. Pulling that loose end causes the entire knot to come undone. There you have it… give it some thought and let me know your thoughts… as I mentioned before, my experience has been positive… but perhaps I’ve just gotten lucky? Naturally, always keep at least one backup plan.