I have long said that science fiction on television, even when it's bad, can serve as inspiration for a budding scientist. Heck, I watched some pretty phenomenally bad scifi TV and movies and a kid, and it fueled the fire of interest and love I had for science. Do I wish the quality of science in the entertainment media were better? Sure! But that doesn't mean it's not serving a purpose.
Science in other media, like the news, is another matter. There, it's critical that it be accurately represented. And it gets worse when someone makes a documentary that's actually a polemic - a persuasive piece meant to change or guide opinions.
That's why I really like this talk by scientist Brian Cox, who makes science documentaries for the BBC and is becoming a science celebrity in the UK. It was the Royal Television Society Huw Wheldon Memorial Lecture which he gave earlier this month on BBC2. he has a lot to say about the difference between documentaries and polemicals, and it's worth your time to watch.
Brian's overriding point is that TV is not fair and balanced, since it gives far more weight to non-mainstream views than is deserved. But this is in the nature of the medium, of course. Brian makes it clear that when a scientist does research he or she must not worry about the audience and must not worry about the conclusion before it is reached; if they do then the work will be hopelessly compromised. But television has the opposite view: it must keep its audience in mind or else it won't make any money.
The thing is, at the heart of this is that the audience needs to know if it's seeing something that aligns with the scientific consensus, or if it's an opinion-piece that may denigrate the actual truth. Usually that's clear, but these days, with increasingly lax rules about what can go on TV, I suspect polemicals disguised as unbiased documentaries will be more common.
Still, as Brian says,"the presentation of ideas must sit at the heart of TV." Even straight, unbiased documentaries can make excellent television. His "Wonders of the Solar System" is an excellent example of that; the demo he does of the retrograde motion of Mars is one of the best I've seen on TV (he shows that clip in his talk). It goes to show you that compelling science can make compelling television, but the science must be allowed to speak freely.