There is no stop and ID law in Michigan. If you are concealed carrying or carrying in a car under the authority of a CPL, you are required to show ID ad CPL if stopped. Aside from that, there is NO law that says you must show ID for no other reason than carrying. Open carrying is completely not mentioned in the disclosure section of the law.
As I told the oakland county sheriff's department, this isn't nazi germany, and you don't need walking papers. Actually, we were eating when they harassed us, so my stupid joke has always been that they should have asked "vere are your mastication papers?"