Continuity mistake: When the little girl runs out to save his father with the "invisible cloak", her mother runs towards the door and it is closed, the shot changes to the street with the girl running, and the door is now open but her mother is yet reach it.
Continuity mistake: In the opening scene where Det. Graham Waters examines the shoe, he moves the lace with his pen. But at the end of the film when we see the same shot again, he prods and moves the whole shoe rather than just the lace.
Answer: If someone stole it, they could fill it with real bullets and since the gun is registered to her father, it would make him a suspect if someone used it in a crime.
moviemogul