“Add a traitor!” was a running joke back in the day. It wasn’t exclusive to Chris Roberts games (although it shows up in Wing Commander II, Strike Commander, Wing Commander III, Wing Commander IV, etc.) but throughout Origin Systems. The big surprise being that there’s a traitor in your midst is used in Wings of Glory and a stack of Ultimas (Ultimae?) (In all honesty, it’s something that makes a lot of sense in game design, especially game design in the early 1990s that was limited to diskettes… because fighting the same bitmaps you use as your wingmen for the rest of the game saves space.)
As for human treason in the Wing Commander universe, a few more examples would be…
* “Burroughs” – the disgruntled flight simulator programmer in “Red and Blue.”
* “Ortiz” – from the WC:CCG’s Kilrathi ‘Traitor’ card. No details beyond that he wears a WC3-era uniform without an apparent rank insignia. (You can read his name on his uniform, which is the same as the artist who painted the card…)
* Admiral Wilson and Captain Sansky – Confederation officers of Pilgrim descent in the Wing Commander movie who sold out to the Kilrathi, provided the NavCom AI and so on.
* Amity Aristee and her crew in Pilgrim Stars and Truth; they didn’t sell out to the Kilrathi… but they did betray and attack the Confederation in the middle of the war.
* The Church of Man in Privateer, especially Righteous Fire (in which the Kilrathi provide them with surplus Salthi to conduct more advanced terrorist attacks in the Gemini Sector.)
* The crew of the Gwenhyvar… or the Johann… or whatever it was. For whatever reason, the dialogue in The Secret Missions suggests that the Kilrathi were forcing the crew to betray the Confederation rather than that they were simply killed and their fighters flown by kils.
And then you get into more broad territory. Does Tolwyn count for betraying the Confederation? What about Doctor Singh for attempting to dose a captured Kilrathi with an infectious agent in On Both Your Houses? And there’s non-humans, like Vidkun the Dolosian leader who sells out the Confederation to the Kilrathi at the 2654 Sivar-Eshrad. False Colors was full of traitors, too! (The whole Y-12 group.)
And as for Kilrathi who were turned, it did happen. There’s even a Confederation ‘Traitor’ card in the CCG that shows one of them. Get a shirt, cat dude:
http://ccg.jetlag.us/index.php/All/c-lu-traitor
There was also a defecting scientist talked about in the Wing Commander Academy (game) manual, Hajjnah. And then there’s the rebels on GHorah Khar, Natanya, Sariha and K'arakh. There’s Bhok nar Ragitagha in The Price of Victory, who attempts to defect to Blair but is ultimately killed. (One big commonality for these Kilrathi traitors seems to be that they have some fairly-unrelated alternative motive… Jukaga wants to get ready for the next war, the rebels don’t love the Confederation so much as they hate the Emperor… Bhok hated the move away from unified clans…)