Open Firearms Carry On Michigan School Properties...

There is growing debate regarding our right in Michigan to openly carry firearms on school property when in possession of a concealed pistol license.

There shouldn't be.

Michigan's law is very clear: open carry onto school property by one holding a concealed pistol license is expressly protected (note that I do not say "permitted - it is a RIGHT, not a privilege), and the federal Gun Free School Zones Act (18 USC 922) also contains a specific exemption for concealed pistol license holders: 

"B) Subparagraph (A) does not apply to the possession of a firearm—
[…] (ii) if the individual possessing the firearm is licensed to do so by the State in which the school zone is located or a political subdivision of the State, and the law of the State or political subdivision requires that, before an individual obtains such a license, the law enforcement authorities of the State or political subdivision verify that the individual is qualified under law to receive the license;"

For further discussion of Michigan's law, I refer you to MSP legal update 86, which states, 

"The above section does not apply to any of the following:
[…]  A person with a valid concealed pistol license (CPL) issued by any state "
https://www.michigan.gov/documents/msp/MSP_Legal_Update_No._86_2_336854_7.pdf

That public schools are government entities and therefore subject to Michigan's firearms pre-emption law is clearly established under both federal and state laws and guidelines.

Under IRS definitions, public schools are "instrumentalities," agencies (branches) of governments: 

"An instrumentality is an organization created by or pursuant to state statute and operated for public purposes. Generally, an instrumentality performs governmental functions… 

In Revenue Ruling 57-128, the IRS addressed the question of whether an organization is wholly-owned by one or more states or political subdivisions. In making this determination, the following factors are taken into consideration:

• Whether it is used for a governmental purpose and performs a governmental function
• Whether performance of its function is on behalf of one or more states or political subdivisions
• Whether there are any private interests involved, or whether the states or political subdivisions involved have the powers and interests of an owner
• Whether control and supervision of the organizations is vested in public authority or authorities
• Whether express or implied statutory or other authority is necessary for its creation and/or use of the instrumentality, and whether such authority exists
• The degree of financial autonomy and the source of operating expenses"

According to census.gov, with only a few exceptions, school districts are counted as government entities.

Under MCL 380.501, "A public school academy is a body corporate and is a governmental agency."

Under MCL 380.1311d, "...the strict discipline academy corporation is a governmental entity."

MCL 380.552"...the school of excellence is a governmental entity."

In Michigan, school districts have the power of taxation through the levy of property taxes, making them government subdivisions.

By all objective measures, school districts in Michigan are local units of government and are covered under MCL 123.1102,

"A local unit of government shall not impose special taxation on, enact or enforce any ordinance or regulation pertaining to, or regulate in any other manner the ownership, registration, purchase, sale, transfer, transportation, or possession of pistols or other firearms, ammunition for pistols or other firearms, or components of pistols or other firearms, except as otherwise provided by federal law or a law of this state."

Schools are trying to have it both ways.  On the one hand, they claim NOT to be government agencies for purposes of avoiding Michigan’s pre-emption law, yet they claim the protection they believe their status as government subdivisions affords them in immunity from prosecution.

They can’t have it both ways.  Their appeal to immunity means they truly recognize their status as local units of government.

Assuming their status as local units of government grants them immunity from prosecution, this argument holds up only in so far as the policies and actions of the government agency are lawful. Government immunity does not provide blanket immunity against unlawful policies or activities; policies that violate Michigan's pre-emption law are clearly illegal, therefore invalidating any claim to immunity.