They all play back as interlaced video to comply with the NTSC standard, but the video itself on the DVD usually isn't. Most films on DVD these days, if not all, are encoded at 23.976 fps progressive, with a flag that tells the player to play it back as 29.97 fps interlaced video. This is much more efficient for the DVD author because it takes up less space since the framerate is lower, meaning that they can get away with a higher bitrate on the DVD.

If the master tapes they're working from are NTSC, then the video is interlaced to begin with and one might think (but not hope) that they would encode it to DVD that way, the lazy bastards.

Let's just hope they have good PAL sources as well and the PAL DVDs come out decent. You know, it might be quite interesting to compare the two versions once they come out to see if they're from the same master.