"He just decided he didn't want to work anymore," was the explanation given to me by a business owner, whose employee failed to show up or call in. This was relayed to her by his friend, who works in the same organization.
If there is only one lesson you can teach your children about the world of business, let it be this. Give your employer the courtesy of two-week's notice. Thanks to social networking, the world has gotten smaller. A future employer may have a connection to a prospective employer. They can and will use this connection before someone gets a chance to get their foot in the door and explain their disappearing act.
So while you are remembering to teach your children to chew with their mouth closed, throw in a few reminders as to how to act in the work place. And whatever you do, be sure to lead by example.