There is a big difference between operating technology that is currently in use without being subject to patent proceedings and operating a technology one knows to be patented without a license.<p>Ignorance is a defence here, particularly for end-users, as this is only potentially tortuous infringement and not criminal. Even for a major corp, if they can't be shown to have been aware of the patent then they can avoid a far greater penalty.<p>You can be told to cease and desist on the basis of a submarine patent on Theora, for sure, but a compliant end-user losing money over this? Not a chance.<p>Incidentally patents only cover commercial activity (at least in Europe).