@JD Yeah you have to watch when you buy at Wal-Mart. It's one of the only places that still sells both widescreen and 4:3 versions of recent movies. But the format should be clearly marked on the back of the box. Similarly, if you're buying, say, the first season of Kung Fu from the 1970s or some movie from 1939 and the box indicates 16:9 letter boxing, then you know something is amiss.
Yeah, once I saw the "this film has been altered from it's original format" screen, I looked again and it turns out that it did say Full Frame in tiny letters that blend in with The Hulk's pants if you don't look closely on the bottom corner of the case. I just didn't think to look when I grabbed it because it was the end of Black Friday, so I was worn out, and I thought that it was new enough that they never would have done a FF version. My mom pointed out the other day that BF stuff tends to be old stuff that they drag out and try to sell off cheap, so I'm thinking that's probably what this was. I did still enjoy the movie, and I probably watch it more times, I just wish I had thought to check the box, because if I had known it was FF, I probably would have dug around longer to see if I could find a Widescreen version, or just no gotten it.