Watching DVDs on Navi with engine off
 

I was thinking about situations where I'd be hanging out in the car for a while and entertain myself by putting in a DVD. I understand it's good for the engine to leave it on idle for extended amounts of time (especially for the length of a movie), but it's also not good to be running the whole movie off the battery with the engine off.
What is the better option?
And is it a serious battery drainer to watch a movie with the speakers loud running on the battery?

Would you be stalking someone to be watching a dvd on "stalking" mode? ^^

best option would be to bring a laptop or something, rather than either draining the battery, or leaving the car idling while watching a movie.

You can buy something like a battery saver where it will cut power to your system so you still have enough for a startup. Or you can pretty much watch at least one movie off a good battery like optima or kintek.