It's funny. In a discussion with a friend at work several years ago, he thought the movies on TV that showed up in letterbox were some kind of cut-rate thing. After explaining it to him he understood.
I belong to Netflix and rent a lot of DVDs. I watch them on a Mac with the 22" Digital Cinema Display. There are no scanning lines. Though I try to stay away from full screen versions, sometimes I don't notice it in the writeup, or want to see the movie so badly that I'll put up with it.
Most of the full screen versions have scanning lines as though they were made from video while the widescreen one usually don't. They seem to be totally digital from film.