I have 1 AR code that works in battle mode though it makes it so as link you cant be killed.so you can actauly use AR codes in battle mode. also i wouldn't use them for wifi.
invincible link/ship works on battle mode
520A7D4C E0821001
020A7D4C E3A01041
D2000000 00000000
try it and you will see that i works.