A payment made in ignorance of a legal right (here, a right of appeal) that would have caused the payer to withhold payment is a payment under a mistake of law recoverable in restitution, and is not 'voluntary' in the relevant sense. The defence of 'honest receipt' as formulated by Brennan J in David Securities does not form part of Australian law and was not adopted by the majority in Commissioner of State Revenue v Royal Insurance. Under the Rules of Racing, a determination of the Racing Appeals Board setting aside a stewards' decision operates as a substituted finding of the stewards for the purposes of AR 173.
The full text is available to signed-in members, including the 9 later cases that cite this judgment.