A friend of mine still calls her parents mummy and daddy. She's 27, and she does it in public.
I asked her once (casually), and she said her parents have always insisted on it and thought mum/dad was disrespectiful.
Fair enough and I know it's none of my business, but I can't help but cringe a bit when I hear adults call their parents this. It just sounds childish and makes me think they're still treated like a child. Then again her parents do still finance her...