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 Section 4-103 imposes a couple of 'reasonableness' requirements on the attempts of parties to use contracts to vary the provisions of Article 4 of the UCC.

Section 4-103(a) forbids the parties to an agreement to 'disclaim the responsibility of a bank for its lack of good faith or failure to exercise ordinary care.' Section 4-103(a) goes on to clarify that 'the parties may determine by agreement the standards by which the responsibility of the bank is to be measured,' but only 'if those standards are not manifestly unreasonable.' Thus, § 4-103(a) allows parties to agree to the standards by which a ...