You've heard "you can't have your cake and eat it too?" It's a stupid expression anyway, but this one is "you CAN have your cake and BEAT IT too. As in scram. Get lost. Sayonara. Later, gator." There comes a time when every kid needs to leave the house, but I've never heard the news get broken over a cake. After the kid moves out all they'll be able to eat is cake anyway (hot tip for broke people: cake is hella cheap and fills you up).
Some parents don't want their kids moving out though. My mom would have loved it if I lived with them for the rest of my life. I always tell her that I'm only one big mistake away from moving back in with them. She laughs at that, but it's startlingly true.