57th found out through espionage that Browncoats was a possible part of plans to help the combined forces of Nemesis and CoJ attack 57th, if they attacked IAA, who were in plans to counter VA.
These plans changed about 10 times over 6 days.
While Nemesis was planning the joint effort, we had no idea as to whether BC were coming in or not. But the idea was that we would be in charge of assigning targets. If we weren't sure BC were coming in, I can't see how 57th were.