That was the first thing that I noticed when viewing the trailer (which is awesome...)
The whole depiction of the professor and Mrs McReady in that fashion was far from the book. And the wardrobe wasn't covered with a big sheet, either (iirc).
My 6 year old daughter and I are reading the series now, just started Prince Caspian last night. I'll have to see the movie first before I take her, I'm not sure how far they'll go in the violence area.
Also, if you watch the high resolution version of the trailer, and stop it when they flash the Queen, that is the scene from the Stone Table, and you can clearly see Aslan bound before you-know-what happens. That depiction seemed very true to the book.
I would definitely check it out first. Some kids manage violence better than others. My daughter I always thought of as a shrinking plant (sort of like MY mother, who can't stand violent movies) but she LOVED LOTR. My son of course even if terrified would never admit it . . . it's a guy thing . . . < g >