Flying free? What a strange idea! That’s like humans or dogs running, or a workout in the gym, or doing something completely natural! How odd!
Doesn’t it look like fun? Yes, its understandable that people worry about free flight. But parrots are as intelligent as a five-year-old child and they know who provides the treats and they know where their home is. They can be trained to come back: recall training.
You should learn from a practiced trainer how to do this, though. Like any skill it takes a someone skilled in training this behavior.