I watched chapter 9 of the DVD version 13 Going On 30 tonight with all 3 (DB, AC, and BC) turned on and I saw no flashing whatsoever. I must qualify that statement, though, as I was constantly bothered by the lack of resolution, lack of color depth, the obvious compression artifacts, and video noise to such a degree that it I had a difficult time trying to spot something as "subtle" as flashing. At the size that I watch things, DVD quality is unbearable and I would never consider watching ANY movie in that format.
I also noted that the gray background in the hallway of the killer scene looked far more uniform in the Blu-ray version than it did on the DVD version. The changing colors of the background in Peter's clip, though exacerbated by his movie camera, were indeed present in the source, though to a lesser degree. DVD sucks!!! I played the scene both on my Oppo BDP-83 and on my HTPC with identical results.
If there was any flashing on my Planar, I could not see it. The only time I have seen the DI work is when I switch from a 100% white pattern to a 0% black pattern instantly. When I do that that, I can see the black level change as the DI closes. I have never seen that same effect happen in real world material to date, though I suppose it could happen under extreme conditions.