no requirements, just walk into any guest relations place (any park & DTD) and ask for the "magical wishes" pin.
if you have the wedding ears, don't be suprised if people just start handing you the pins. it seemed as if we weren't wearing the pins, we'd get another set. we must've ended up with 5 sets. we ended up giving a bunch of them away to newlyweds that we might have spoken with that didn't have ears or pins.