Strange Signs

We just got back from a long and delicious dinner at a friend's house. I'll tell you all about it tomorrow, since it's after midnight here which means I'm nearly a pumpkin.
I saw this sign yesterday and couldn't figure out what it meant. (Ignore the graffiti. I'm talking about why the state or the city would put up a sign like this.)



Why would it have a line drawn through a parent and child holding hands? The other side of the sign clued me in on the way back. Does anyone have any guesses?