"So a year played in Florida will count toward the four total when a player transfers to a Maryland MIAA school?
As an aside, What does this rule do to the defender on FCA Blue and the 2 kids on Crabs that turn 16 this spring/summer as that will put them older than 19 before August of their senior year?"

For the Florida kid does this mean that Andy only gave him a 3 year scholarship. As far as the MIAA kids, I doubt that they even check birthdays. If they did Gilman football and BL Lax would blow.