When you have no AWACS in the mission, your call is transfered to "Strike" on the carrier. And, unfortunately, he seems to know more than AWACS.
I've investigated methods of turning him off, but I ain't found one yet. Even deleting the carrier doesn't do it! "Strike" is the All-Knowing, Ever-present, Voice of knowledge as far as I can tell.
If anyone knows how to turn him off, I'd sure appreciate the hint.