(iv) Too Much Restitution
The generally restrictive approach to the interpretation of the law of unjust enrichment means that the defendant’s receipt of the benefit is secure save in the exceptional cases where the claimant establishes that the defendant’s enrichment is unjust. This principle of security of receipt is important to the law of restitution, especially in the commercial field where parties generally need to be certain that benefits have been effectively transferred and will not be upset too readily. It is consequently consistent with the principle of respecting the parties’ autonomy, which is particularly important because unjust enrichment liability is strict.[1] A move to an absence of basis approach might destabilize commercial transactions by allowing for too much restitution.87 Birks recognized this and, for that reason, he considered that identifying an absence of basis only means that a prima facie case for restitution has been established.88 The emphasis then shifts to the defences. But his analysis of the defences was much wider than the orthodox exposition and much of his analysis was too vague to be commercially acceptable.
- [1] 88 Birks, Unjust Enrichment (2nd edn), 263.
