The reason why untrustworthy people can't reserve commemorative coins is because they have bad credit records in the banking system. Banks will evaluate the applicant's credit history when granting loans or conducting other financial transactions. If the applicant has a record of dishonesty, the bank will think that the applicant is at risk of breach of contract, thus rejecting the applicant's application. Moreover, the reservation of commemorative coins requires personal information and identification. If the untrustworthy person cannot provide information or proof, he will not be able to reserve commemorative coins.