Oh, that's a quarantine flag. Warning that there's Black Death aboard. And an annoying kid.
I know that it's a pretty cheesy old family movie, but there is something endearing about the Swiss Family Robinson. It also has pirates, which is cool. The treehouse that they build to live in is ridiculous though. We always tried to copy what they did when we were kids and playing outside. Not possible. We didn't have the advanced skills in engineering and architecture. We had duct tape and twine.