A friend told me that Netflix will probably continue allowing this in the hope that the freeloaders get a taste of what the service can offer them and sign up for their own accounts. I think the company can do more to incentivize that, such as tweaking the algorithms to be better responsive to individual viewers. If five or six people are all using the same account, you could have an over-eclectic smorgasbord of suggestions that wouldn't be very helpful. There's also social networking features, though in my personal opinion it's hard to execute effectively.