As there is no legal beagle section on here, I thought I would post this here. After having been asked about this particular law several times, I thought I would clarify what I know to all on here. The law is MCL 28.425o(a). The law says "an individual under this act to carry a concealed pistol, or who is exempt from licensure under section 12a(f), shall not carry a concealed pistol o the premise of . . . a school or school property except that a parent or legal guardian (emphasis added) of a student of the school is not precluded from carrying a concealed pistol while in a vehicle on school property, if he or she is dropping the student off at the school or picking up the child from the school. As used in this section, "school" and "school property" mean those terms as defined in section 237a of the Michigan penal code . . . MCL 750.237a"
So based on my personal experience with this section in the court system (limited exposure not statewide), if you are not a parent or legal guardian of a student of the school and you are not dropping off or picking up your child, then you have violated this law.
What won't work: Grandparent picking up after school; Parent taking child to school property to play on weekends and child does not attend the school; Taking the neighbor's child to the school and your child is home sick; or Parent driving onto school property to attend parent-teacher conference without your child.
What is questionable: driving to school to watch your child participate in an afterschool sport or club and then taking your child home; a parent attending a private tutoring lesson with their child at the school and the tutor rents space from the school.
Finally, the last two parts of this equation are the county prosecutor and the judge that will be ultimately assigned to try the case. As the prosecutor sets the tone and the judge has the final say.
What can you do to avoid violating this section. Park off of school property (be sure to find out exactly where school property ends), switch to open carry and walk onto the school grounds. Also remember that if you do not have a CPL (not called a ccw because that is a felony in this state and not interchangeable), you cannot carry in any way on school property (see MCL 750.234d).