It can be found that according to the introduction of banking professionals, a certain limit value (different bank standards are different) is generally set for the small payment limit without confidentiality and visa, so as to prevent the abnormal amount of funds from being paid without confidentiality and visa. Banks are very strict with merchants who apply for small-amount confidential and visa-free payment POS machines. They must have certain qualifications and real-name account management. Not any merchant can apply for opening at will, and the flow of funds is very clear. If the POS machine is stolen, the public security organ and the bank can easily find out which merchant swiped the ETC card.