We stayed at AKL in august and we had 2 year old twins. The Balconys themselves are safe, however do not forget there are animals out there>....That they really want to see. so they will be more inclined to climb to get a better view. First of all the little table that is out there.... put it in the room first thing. Mine tried to use it as some kind of step stool. They were only allowed out there with an adult and were not allowed to stand on the chair. That being said at that point they could not unlock the door, at this point 2 and a half. they can unlock and open everything.....We purchased for around ten dollars, I believe from Walter Drake? A mini alarm that you attach to the slider, we will be in a villa with at least 2 balconys so we have one for each door. That way if they start fooling with the door I will know in an instant. I don't know how much of a Houdini your guy is, But for your sanity it may be worth the extra layer of vigilance. Good luck.