It's probably a poor excuse, I d/load so I can try before I buy.
I got so sick of paying to see a movie and feeling ripped off so now if I like a movie I WILL go to see it at the movies or buy the DVD.
If it's no good, meh, there's an hour of life I'll never get back.
I think out of the last 5 DVD's I bought, I wouldn't have bought any of them if I hadn't known the movie was good.
If the movie people want my money, they need to make sure the rest of the movie is as good as the trailer. I hate seeing a good trailer and finding out the rest of the movie is pathetic.