It depends on what you are watching. If you are just trying to turn your mind off and just plug into anything, any frivolous stuff or harmful violent movies, etc., then it can be detrimental to the mind. So I would be very careful what you watch, because everything has an effect and will come up in the mind later.
Keeping informed sometimes can generate a compassionate response; I happened to be in a situation where there was a TV around and they showed a documentary about old widows in India and what they have to go through, and I watched it. It was extremely helpful for me because I realized what those peoples' lives are actually like. It is very difficult to get lost in self-pity when you understand how other people live in certain areas of the world.
So it really depends on the program.