User blog comment:Arthurlover7/Is there a traiter in Camolot??/@comment-5674726-20121105000027

It depends on what Gwen is doing when she gets kidnapped.

Pictures from the episode show her and Elyan at a grave. If that's where one or both of their parents are buried, it could be the anniversary of a death. Gwen was Morgana's maid for years so, if she was in the habit of visiting her mother's grave every year on the anniversary of her death, Morgana would be able to anticipate this year's visit, and quite possibly guess that Gwen is unlikely to have many knights escorting her on her pilgrimage.

The idea of a traitor in Camelot is also intriguing, though.

Morgana also visited Camelot very recently, in her guise as Hilda. Maybe she planted a magical listening device.