I'm sure it has happened before. Probably Asian releases or small studios (Fox Lorber strikes me as the kind of studio that would think this is a good idea). But it wasn't Warner Bros. Their discs are true anamorphic. It just took them a while to figure out how to do digital compression.

I myself thought some of my non-anamorphic dvds (i.e. THE THING, THERE'S SOMETHING ABOUT MARY, RISING SUN....etc) were actually anamorphic on my widescreen TV - simply due the fact that the image filled the entire screen. However, what I later discovered is that the ZOOM feature on my widescreen TV inexplicably activated with these titles; thus blowing up the image. I probably would have continued to think that these titles were anamorphic if I hadn't realized a significant amount of the picture was cropped out.