I think a lot of it is to do with the actual chance that the individual is going to get charged with it, big companies generally go after the Distributors and not the individuals regarding it. Plus staying online that you did something doesn't prove that you actually did it so they would still have to get solid evidence that you actually did it which costs money A lot of times more money than they would have lost from the pirating activity in the first place which is why a lot of them just settle for sending a dmca to the ISP and the ISP for as it saying LOL you better not be doing this