Typically, an employee is entitled to see their time card and have a copy of it for their records, to check for errors, etc. That having been said, the mechanism for doing so is set per company policy. In this instance , having to go through your suspervisor. The fact is that most employment is "at will" which means that a business can set the conditions of employment much as it sees fit. That is unless an employee's treatment constitutes some for of legally actionable discrimination. Also, it must not violate the terms of any applicable union agreement or employment contract.