A company the size of Facebook can't really get away with that scheme even if it were intentional. For one thing, I can sell the patent to a troll and let them do my dirty work. Or a company could buy you solely to get fuel to sue Facebook over.

If Zuckerberg signs a paper with the wrong title, there's a troll lawsuit the next day. So if you make a habit of "in practice" strongarming people, you can easily slip up and have a huge headache on your hands.