"Crossfire"

[Error.]

If they shoot into a crowd trying to kill the T but ends up killing/damaging a bunch of other Ts... it’s not crossfire

[Infinityward]

Crossfire is when a CT is trying to shoot a T that is not following an order/rebelling, and other Ts are shot/killed in the firefight. Most of the time it is not freekilling, but if a CT is clearly going out of his way to "crossfire" then he can be punished. But the vast majority of the time crossfire is simply that, an accident. CTs do not have to slay for crossfire, but if an admin deems they're abusing the rule to freekill or carelessly spraying people down they can act.

 

^ From the FAQ.

 

If a CT is being careless and sprays into a stack and damages/kills multiple people then they are subject to punishment if an admin deems so.