How did they film the cutting scenes in the movie thirteen?
I'm not 100% sure this is correct, since I wasn't in the movie. BUT I was in theater for a long time and what we did when there was a scene like that was put theatrical prosthetic "skin" on the persons arm to make it look like wasnt even there then make a cut in it and fill it with fake blood. That way when the person was cut, it would cut the fake skin and blood realistic looking blood.
PL Travers did not like the movie. She had expected to be able to have a say in cutting scenes, but this did not happen. Disney was even reluctant to invite her to the premiere of the film, as he believed she would be too openly negative about it - which, indeed, she was. She felt that the film took away from the integrity of the character she had created in Mary Poppins.