Michigan Compiled Laws, Chapter 51. Sheriffs § 51.283

Sec. 3. A copy of the rules and regulations, and good behavior allowances for obedience thereto and compliance therewith shall be posted in such place or places in the county jail as will enable all persons imprisoned therein to become acquainted therewith, and it shall be the duty of each prisoner entitled to release with the credit for good behavior allowance to call to the attention of the sheriff or any of his deputies the fact that he is entitled to release, and no sheriff shall be liable to respond to any prisoner or former prisoner in damages in any form of action, particularly false imprisonment, if any excess time up to the maximum of the original sentence without good behavior allowance be served.