obviously if you play with randoms it won't happen but if you can play with friends i can see it happening. that was what i first expected when they said zombies was 8 players. if you can have 8 players working together it could be pretty damn awesome. i'm sure power ups will only work for your team but sounds like you can have twice the killing power at least.
definitely interested in that mode...although i'll have more fun just screwing over randoms in it.