I believe you to be correct you don't have to belong to any district, in fact I know of kids who live in certain districts but attend others and play sports there also it happens even in public schools for whatever reason. However Let's say the same Scenario, but let's say Public school A hires Public school B's junior high football coach to be there next high school coach. He knows there is a great 8th grade class coming up in Public B so he would like 9 of them boys to follow him knowing they will play only for him next year, he even tells the administration in the interview, listen these boys will come play for me if you hire me, but they don't have a lot of money what sort of scholarship can your booster club offer them to come here? Public School A says we cannot offer a scholarship they will have to pay normal out of district tuition as all normal kids do. Public A still hires coach just 4 kids follow, but Public B checks the box they moved for athletic reason MSHSAA sides with Public B kids are ruled ineligible for that year they move back to their regular district. End of story.
But now lets say Public A is now a Private school. Same thing goes on except now Private A's administration agrees that they will pay for all those kids tuition and goes ahead and hires Public B's Junior high coach. 9 boys follow all of them on full ride scholarship.Public B checks the box Private says they left for safety reason MSHSAA says okay whatever. Somethings are said Public B refuses to play the private school, the new private school coach interviews because he is upset about things being said and schools not playing him....says hey people don't know those kids were going to play for me no matter were I went. MSHSAA continues to turn a blind Private school fan or coach comes on the local sports board going whatever you are all just haters, we are doing nothing wrong blah blah blah. Rules are all good and they apply equally which we all know they don't.
Case closed.