Yeah, I saw that page before. I think I got the idea originally from there, although I didn't remember it until now.
Since my Atari died I haven't done many experiments with TV color and stuff, but I remember about the color artifacts in high resolution mode, and that the actual results varied depending on the monitor or TV set, color technology (PAL or NTSC) or even the particular color graphics chip in the computer. I guess this must be something similar. However, with wide pixel graphic modes such interference would be less likely to reproduce... although you probably won't get the blur either...