Did you look at my link to a severe case of moire with a Canon 5D? It is nothing to do with the camera, just an unfortunate case of conflicting frequency.
Yes, I have read your post about the 5D. Interesting. The poster there has many varied images which suffer from the same problem, yet I can't find anything else on the internet about moire and the 5D. Possibly a defective filter? Modified camera? Or a genuine problem which the poster was able to freely reproduce, and I've not found other examples of?
Whichever way you look at it, once baked into the image, moire is a real pain to eliminate. I'd still argue that the effect is to do with the camera - film wouldn't do it after all. A good AA filter should eliminate moire.
Returning back to the 1D, it does definitely have an AA filter:
Quote from: Canon Museum
Low-pass filter Located in front of the CCD sensor, non-removable
However, it seems like my findings about the weakness of the AA filter aren't alone:
Quote from: DPReview
Canon have noted previously that they are using a 'less powerful' (eg. less intrusive) anti-alias filter in front of the sensor. This improves sharpness but does increase the amount of work which has be done by the cameras internal processing algorithms to remove any artifacts created by high frequency detail (moiré patterns). On the whole this appears to work very well, the camera delivers great resolution. But there were occasions (a very small % of my shots) where the right type of detail at the right frequency was able to bypass Canon's trickery and appear in the final image as a moiré pattern.
And, of course the previously mentioned Fred Miranda review. So I guess my experience isn't isolated, so the camera was no doubt operating as it was designed.
To me it seems like you're lucky to have got away without moire, but the weak AA filter combined with poor in-camera jpg processing, and you using raw could be the key to the differences we experienced.
Whichever way you look at it, those 1D images I posted are not examples of images taken without an AA filter. If it was shot without an AA filter, the moire would have been even more pronounced.