I don’t understand. How is it useful for Netflix to show me movies that they don’t have? And how hard is it to implement search over their catalog when they only seem to have about 100 movies?
That might make sense in an abstract way, but no, that's not what people expect. If I'm searching for something at Netflix, I don't want the answer to "does it exist?", I want the answer to "do you have available for viewing?".
In the more general sense of the search topic, I don't want a search to return things they don't have. If it's out of stock, say so prominently. Don't make the user click through to the item itself only to see "out of stock".