I haven't had an incident yet, but I'm way more careful with a young kid (or myself). Leaving one charging on a couch, for example, isn't something I'm comfortable with both because of it sliding a foot or two on to the carpet or bending the connector.
More annoyance comes from removing of the charging indicators that were on the magsafe port. The only clue is a small "ding" sound when it starts charging, but is easy to miss and won't happen in deep sleep. I've plugged in a laptop not noticing someone had unplugged the other end until the next morning my computer was still dead. It was also nice that you could see that amber charging light turn green so you knew it was charged without opening the lid and waking it up.
More annoyance comes from removing of the charging indicators that were on the magsafe port. The only clue is a small "ding" sound when it starts charging, but is easy to miss and won't happen in deep sleep. I've plugged in a laptop not noticing someone had unplugged the other end until the next morning my computer was still dead. It was also nice that you could see that amber charging light turn green so you knew it was charged without opening the lid and waking it up.