35. Protection of security by the law on unjustified enrichment. The rules on unjustified enrichment respect the binding force of contracts in that a valid contract between the parties will provide a justifying basis for an enrichment conferred by one party on the other within the terms of that contract.54 The rules on unjustified enrichment buttress the protection of rights within private law by the principle that a wrongdoer is not permitted to profit from the exploitation of another’s rights. A non-innocent use of another’s assets as a rule creates an obligation to pay for the value of that use,55 so helping to remove any incentive to make improper use of another’s property. Protection of reasonable reliance and expectations as a value and aim is relevant to both the elements of the claim and the grounds of defence within the rules on unjustified enrichment. A person who confers an enrichment on another in circumstances where it is reasonable to expect a counter-benefit, or the return of the benefit if events do not turn out as expected, is protected by being entitled to a reversal of the enrichment if the agreement on which reliance was placed turns out not to be valid or if the mutually anticipated outcome does not occur.56 Equally, the interests of the recipient of a benefit are protected if the recipient relies on the apparent entitlement to the benefit received. Such protection is conferred by the defence of disenrichment, where the recipient disposes of the benefit in a bona fide assumption that there is a right to do so,57 or by a defence, protecting faith in the market, where an acquirer has given value to a third party in good faith for the benefit received.58

Property

36. Security a core aim. Security is a paramount value in relation to property law and pervades the whole of Book VIII. The rules in Chapter 6 on the protection of ownership and possession provide a

54VII. – 2:101(1)(a).

55See in particular VII. – 4:101(c) and VII. – 5:102(1).

56Cf. VII. – 2:101(4).

57VII. – 6:101.

58VII. – 6:102.

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particularly clear example. Indeed, in relation to the acquisition and loss of ownership in movables, certainty and predictability of outcome may sometimes be more important that the actual content of the rules. Different approaches, even fundamentally different approaches, can all lead to acceptable results. Again, however, different values have to be balanced against each other. Some methods of increasing security might, for example, inhibit easy transferability. And certainty has to be balanced against fairness, as can be seen very clearly in the rules in Book VIII on production, combination and commingling.59 It almost goes without saying that security is also a core aim of the Book on proprietary security. The whole objective is to enable parties to provide and obtain security for the proper performance of obligations. The rules are comprehensive and cover all types of proprietary security over moveable assets, including retention of ownership devices. They aim at maximum certainty by recommending a registration system for the effectiveness of a proprietary security against third parties.60 A large part of Book IX is concerned with the detailed regulation of this system. Its rules provide effective remedies for creditors wishing to enforce their security.61

37. Protection of reasonable reliance and expectations. This value is strongly reflected in Book VIII. It can be seen most obviously in the rules on good faith acquisition from a person who has no right or authority to transfer ownership62 and in the rules on the acquisition of ownership by continuous possession.63 In the Book on proprietary security this value is most obviously reflected in rules protecting the good faith acquisition of assets, or of security rights in assets, free from a prior security right.64

59VIII.–5:101 to VIII.–5:105.

60Chapter 3.

61Chapter 7.

62VIII. – 3:101 and VIII. – 3:102.

63VIII. – 4:101 to 4:302.

64IX. – 2:108, IX. – 2:109 and IX. – 6:102.

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