Whenever forced to use one of these authentications, I just wail on the keyboard to provide an answer. My mother's maiden name? Why, it's "sfdgh,jsdzl.kg hjsldghs,hb".
Whenever i need to open an important account (say, with the power utility) I make up answers and record them on paper. Simple. Effective.
Combustible.
They'll get an earfull when they ask me for it though, futile or not :)