I have a strict policy of showing DVDs and films with the subtitle option on. The reason for this is twofold: students comprehend more of the film and its nuances, and students engage in the act of reading. Students never watch a film just to watch it in my class. They always have viewing questions, and the movie is curriculum related. My hope is that this method of presentation will improve the quality of the experience for the classroom.
Oh my gosh, that is a brilliant idea. My experience is that students listen best when literature is read to them. The listen, the pick up, and the retain more. This is a brilliant idea to make videos more productive. Students will read it, there is no doubt. They won't be able to stop themselves. I rarely show films because we've had teachers abuse that and only teach literature if it has films. This, however, encourages me just a little more that I can validate its use in my classroom.
That is funny, I really thought I was the only one who did this. It actually happened by accident the first time, as the subtitles were already on and we couldn't find the correct remote control to turn them off. My class actually liked it much better, probably for the first reason you stated. I also noticed they paid much more attention (imagine that!).
One problem I have always experienced is hearing the movies in classrooms next to me, literally blaring through the walls. Finally, we have a large enough ESL population in most of our NC schools, that many students NEED the subtitles (even reading the English is helpful for them). I think turning subtitles on is actually a solution to many problems.
Sounds like you've got a good thing going in your classroom. I don't use movies in their entirety very often in my classroom, and a short scene or two generally keeps students' attention, I find--probably because it's a rarity. I have shown pieces of the Gerard Depardieu version of Cyrano in French and a scene or two of Life is Beautiful and had to use subtitles for both. The subtitles for Life were well done; unfortunately, the Cyrano subtitles were ridiculous and weak compared to the writing--which is why I showed the scene, actually. In short, then, to answer your question--no.
Not usually, but I did just show Motorcycle Diaries with English subtitles, because, of course, the movie is in Spanish. I also have a lot of native Spanish speakers in my classes, and I know they got more out of the Spanish language version of the film, as a lot was lost in the translated subtitles. Usually no, however.
Of course, it's annoying when something or someone interrupts the film and you missed out of something that's been said in the film. Having subtitles on doesn't mean you're impaired or anything. It gives you a better idea of what's been said and you're able to understand the film better.
And...it doesn't get in the way of the movie. Because everyone can watch the film and see the subtitles at the same time, can't they??