Well, no. That is not a possible explanation. You can’t take a color scan and a black and white scan of a piece of paper both at the same time.
If you watch Karl Denninger’s YouTube video, you will understand why what you suggest is impossible.
http://www.youtube.com/watch?v=2eOfYwYyS_c&feature=player_embedded
1. The original was photocopied on the safety paper, using a black and white copier.
2. Either there were no fringes for whatever reason, or it was retouched to remove the fringes. Possibly fancy scanners do this automatically, I wouldn’t know. He claims all scanners create those fringes when his does, I don’t know if that is supportable.