Update: Though I'm still not certain, I think the problem is related to the "Voice recognition" checkbox in the Launcher. I turned it off and didn't get any mysterious auto-comm coming up... well, at least until I force-quit out of the game.
Come to think of it, I think the menu went beserk on the AI comm messages... must be my cable connections. But then again shouldn't it be impossible? I mean, I left my microphones on mute...
Which reminds me - does anyone know how to get voice working in FS2O? As in, voice messages for multi games, like in HL2 or CSS where you hold down +voicerecord for a constant feed and stuff? The in-game menus complain of DirectSoundCapture among other things.