Give me a break. Seriously...have you no human empathy? Gross.
Bulletin! You do not have to be "ignoring" your child for your young child to suddenly and impulsively do something you did not expect - like running into the street, jumping off something, leaning back in a chair, hitting someone, or - yes! imagine! - reaching over the side of a boat. (And if your child, like two of mine, has ADHD, they'll do things like this even more often.)
Accidents happen. Not because society has gone to hell in a hand basket and all parents are crap (because accidents are a totally new thing, that just started happening in the last few years). If anything, most the parents I know are OVERLY attentive, hovering over their children. But kids' brains aren't fully developed yet and they do stupid, reckless stuff that you can't always anticipate.