from what i seen of that battle, looks like non faction members can get half way across the bridge inside the SL base, and when the non faction tamer tell their pets to kill, they stand there shooting u with spells, not sure if the pets can get past the faction line, cause the bridge was pretty crowded but i know the non factioner couldn't get past.
anyway, this is also lame! they should block about 5 screens east, west, north, and south around all bases, that way no [censored] non factioner can get near the fight:/ if u want to fight u should have to join the faction, very simple!