通常，法院因此而并不探究约因的充分性。在一方双方交换的价值不确定或者难以计算时尤为如此。但这即使在交易很明显是协商和赠与的混合的情况下也是适用的。参见第71条的评论c。约因的重大不充分可能与能力、诈欺和相似性问题相关，但是，除非在事实上没有协商的案例中，约因的要件并非针对轻率的、无远见的契约的安全保障措施。
　　Illustrations:　
　　例释：
　　3. A borrows $300 from B to enable A to begin litigation to recover a gold mine through litigation, and promises to repay $10,000 when he recovers the mine. The loan is consideration for the promise.
　　3.A为了能够开始一项通过诉讼而重新获得金矿的诉讼而向B借了300美元，并允诺当他重新获得金矿时将偿还10,000美元。借款就是该允诺的约因。
　　4. A is pregnant with the illegitimate child of B, a wealthy man. A promises to give the child A''s surname and B''s given name, and B promises to provide for the support and education of the child and to set up a trust of securities to provide the child with a minimum net income of $100 per week until he reaches the age of 21. The naming of the child is consideration for B''s promise.
　　4.A怀上了富人B的非婚生孩子。A允诺将给予这个孩子自己的和B的教名，B允诺将提供这个孩子的抚养和教育费用，并设立一个有价证券信托，以在这个孩子21岁之前每周为其提供至少100美元的净收益。对这个孩子的命名是B的允诺的约因。
　　d. Pretended exchange. Disparity in value, with or without other circumstances, sometimes indicates that the purported consideration was not in fact bargained for but was a mere formality or pretense. Such a sham or "nominal" consideration does not satisfy the requirement of § 71. Promises are enforced in such cases, if at all, either as promises binding without consideration under §§ 82-94 or as promises binding by virtue of their formal characteristics under § 6. See, for example, §§ 95-109 on contracts under seal.
　　d.虚假的交换。在有或没有其他情景的情况下，价值的不同有时意味着声称的约因在事实上并未经过协商，而只是一种单纯的形式或者伪装。这种虚假的或者“名义上的”约因不能满足第71条的要求。这样的允诺是能够执行的，如果它们是作为第82-94条下的无需约因的允诺或者是作为第6条下的依靠形式特征的允诺。参见，例如，第95-109条中关于铅封契约的规定。

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