It's an old English nursery rhyme from the 18th century:
Ladybird, ladybird, fly away home
Your house is on fire and your children are gone.
As with most good nursery rhymes and fairy stories, the tale is very grim and there is no happy ending. In our sanitized 21st century awash with political correctness and drowning in feel-good revisionism, it's instructive to go back to the good-old-days when fairy stories would scare the shit out of kids and stories would end with people being killed, eaten, lost, or possibly all three.
Here is Second Life, the grim and the tragic is still alive and kicking, despite the banning of gambling and banking. Only yesterday my friend IMed me to say that she had accidentally burned down the house. No, she was not at a dance ("We don't need no water let the motherfucker burn") nor listening to Talking Heads ("There has got to be a way, burning down the house." No, turns out she attached to the wall a torch that she had picked up free some months ago, only to find that it contained a script for raising homes to the ground.
Fortunately only the house burned down and not the entire sim: Try explaining that to the neighbors!
And the moral of this cautionary tale? Buy fireproof houses and be very very careful with free stuff - you don't know where it's been.