Check guaranty card programs, customer-sponsored credit card programs, and similar arrangements in which a bank undertakes to guarantee the obligations of individuals who are its retail banking deposit customers are exempted from § 337.2: Provided, however, That the bank establishes the creditworthiness of the individual before undertaking to guarantee his/her obligations and that any such arrangement to which a bank's principal shareholders, directors, or executive officers are a party be in compliance with applicable provisions of Federal Reserve Regulation O (12 CFR part 215).