Can anyone please explain playing up an age level to me and who actually guides this and decides how many kids can play up? Can kids play up if it is a "pure team?"  Can players play down if it is a minor pure team? Does it matter if the team is Tier I vs II? Is it USA Hockey, local league (AHF, NJYHL, AYHL, etc) or based on the organization itself (Black Bear). Just looking to clarify what is a murky mess and understand. Would love a link to an actual policy on this :-)

Not looking for benefits/downsides to it. Not even for my kids. Just trying to understand the drama around our rink and get a clearer picture of what our teams will actually look like next year.