If you saw the casino parking lot video, you’ll notice her arms are dangly and head bobbing. He is practically dragging her. She is also swaying with dangly arms walking into the hotel room.
It was said he gave Natalie the date rape drug too.
Which video showed the parking lot?
In the ones I've seen, she follows him under her own power. Example:
http://www.youtube.com/watch?v=UgGQk8G7sF4
Bear in mind, surveillance video is usually at a lower frame rate than normal video, in order to conserve storage. All motion looks strange and unnatural.