I think that most of the dangers that come from this is from being careless... Me being one of those. I may be uneducated in this, reason why this post was started, but still classify myself as a careless one. I am wondering about how would an electrical mishap or tank break cause anything bad on your family? Being careful in this hobby is the name of the game? From what I read almost everything in our tank has some form of toxins to them. Why does your hand feel funny when you brush past your anemone? You wouldnt have a foxface to eat your algae then right? Their barbs have poison? Its all about being careful.
I'm not saying do what you feel is right at all, but just be educated. Every part of this hobby, the hobbyist needs to be educated. That is why this wonderful forum exists.