Try before you buy is a possible defence which could actually upset laws on a number of cases.
Take me ... I'll download a movie and if I like it, I'll buy it. If I think it is a laod of trash then I count myself fortunate that I haven't wasted my money and shelf space on a film that I hate.
Most recent purchases have been a couple of Edie Reader CD's, Kung-Fu Panda and Battlestar Galactica (the whole series; just waiting for the proper 20 episode series 4 to surface) among others
Recent failures were Wall-E and Pink Panther 2.
It is long time that the movie and music companies were actively legislatively stopped from being so greedy. I do believe that if people walk out of a film in a cinema up to half way through, that they should get a full refund if the product fails to live up the hype.
I'm not saying this without having my own irons in the fire. Some twit on Amazon wanted £60 for a copy of one of my books ... will I ever see anything from that? Nope. They've also dropped the price to £20 recently!!!
But the movie and music industry want more money from single works for much, much longer. They want an income for life for a bit of hard work; this is more than anyone else has got. Why should they be allowed to be so greedy?
String 'em up from the nearest yard arm I say. Hoist by their own petard.
Nah, as far as I am concerned, downloading is a realistic try before you buy option ... provided you can prove that you are, actually, buying what you like.