It came up in a chat with the owner of a chain of three gastronomic establishments: "I bought an app so staff can clock in with their cell phones. Does that cover me if an inspection happens, or will they still ask for the paper timesheet?". The doubt is reasonable and the short answer is surprising: Argentine law does not force you to use paper, nor an app, nor a biometric clock. What matters is not the format. It matters that the record is reliable and serves as evidence. Here I explain what makes a clock-in app work for a Ministry of Human Capital inspection and what turns it into useless paper.