Abdur-Rahmaan ibn Mahdee (rahima-hullaah) mentions:
We were with Maalik Ibn Anas when a man came saying: ‘O Abu ‘Abdullaah, I have travelled a distance of six months. The people of my land sent me to ask you about a matter.’
So he said: ‘Ask!’
So the man asked him some things, so he replied: ‘I do not know’
…and the man thought he had come to someone who knew everything, so he said: ‘What shall I tell the people of my land when I return to them?’
He said: ‘Say to them: Maalik Ibn Anas does not know.’