When I was a kid my best friend George was a fan of Superman. One day he got into his head that if he had his special Superman cape on then he just might be able to leap off his front veranda and fly. Sadly gravity intervened and fortunately the veranda height and young green bones prevented any serious injury, other than the wack on the behind from his Mom who caught the act.
Now when I do an inspection, I always think of countless young Georges and Goerginas and how they can find ways of getting into risky situations, through their playful behaviour.
Decks, balconies and staircases can all present a situation where a child's safety may be compromised if they can get through the protective side barrier. A good rule of thumb is... if my clenched fist can make it through the vertical guardrails, then so can a child.
Look at the photos above. From afar, the deck looks well constructed. However on close-up, when applying the 'fist test', the protective barrier needs attention. In this case, adding intermediate struts or changing to say clear solid panels are good options for 'kidproofing' the deck.