Stating the obvious and talking during a movie?

I think it's a habit that some people have and most of the time don't even realize they are doing it. I have an aunt who does this and what's worse if it's something she has seen before will tell you what will happens next. So one day i just confront her. I a very honest and sincere way I told her that it's understandable to get excited about a good scene in the movie but often time it ruin the movie and that i really enjoy spending time watching movies together with her and still would if she does the talking out loud but it would be less of a spoiler if she didn't. My tip is don't do this confronting while watching a movie wait until you are doing other task, like cooking together or eating lunch or whatever just not during a movie. My aunt still does it but she caught herself now and rarely ever happens when we watch movie together now.