Medina Square will have the people chanting, you will see the cutscene and get booted out.
If you re-enter there will be people guarding the entrance, they taunt you for being human and such but won't let you through.
(this later stuff won't be added till later on)
After Magus it will be people worshipping Ozzie, you can enter the Square but no one will be nice to you (no battles though because it's a shrine -- though maybe a battle on Ozzie's shrine would be an honor to him?)
After Ozzie, the Square will eventually upgrade to a mini-fair, like Leene Square only on a much tinier scale. There will be mini-games here that aren't at the Millennial Fair (if I can think of some mini-games).