An article in the New Zealand Free Lance 6th August 1930 talks about a man who was brought up by a foster parent and he used their name by adoption. This man became a leading man in Palmerston North though the article doesn't mention who he was. A problem surfaced when the gentleman was about to be married to a well-known resident of the embryo city.
His real mother desired the secret to be kept, for she had no other children and was also well known.
The Registrar of Marriages, being acquainted with the delicate problem of what name to use legally on the certificate of marriage, wrote to the Chief Justice of the time, Sir Robert Stout and received the reply :
"A man may legally acquire a name by reputation."
The gentleman then married with a clear conscience.
I read a comment by a person who once worked in bdm, she said, "Until 1986, you could be called by any name you wished and have this endorsed on your birth certificate". So it stands to reason that the name used on a marriage certificate could be the one you were usually known by.
That makes searching for people a bit more difficult though.