Stuart Stone
http://www.lawlink.nsw.gov.au/lrc.nsf/pages/R61CHP2
2.1...'The use of surnames appears to have been more a response to the needs of state and church administration (the exchequer, legal transactions, tenants' rolls) than for purposes of self-identification.'
2.13... 'The common law recognises an adult�s right to change his or her name. Provided there is no intent to defraud or deceive and inflict pecuniary loss on another, a person may assume any new or additional name including one which is used by another.'...
Makes no mention of a child/baby's name being changed in order to defraud, deceive and inflict pecuniary loss on another...cheeky bastards!!