You have to write some relatively complex law to prohibit it. For example, Google bought Motorola Mobility -- do they get those patents? What if they then spi

You have to write some relatively complex law to prohibit it. For example, Google bought Motorola Mobility -- do they get those patents? What if they then spin off everything, but the patents? Can they do that? Whom do the patents stay with? Can I sell you my company, but not the patents? As an employee, when I grant my employer my patents, have I sold them? Etc...