New Scientist reports that Philips has filed a patent for technology to force viewers to watch the ads in a program. Basically they plan to add extra flags to the Multimedia Home Platform that would stop controls from working until the ads are finished:

If a new idea from Philips catches on, the company may not be very popular with TV viewers. The company's labs in Eindhoven, The Netherlands, has been cooking up a way to stop people changing channels to avoid adverts or fast forwarding through ads they have recorded along with their target programme.

The secret, according to a new patent filing, is to take advantage of Multimedia Home Platform - the technology behind interactive television in many countries around the world. MHP software now comes built into most modern digital TV receivers and recorders. It looks for digital flags buried in a broadcast, and displays messages on screen that let the viewer call up extra features, such as additional footage or information about a programme.

Philips suggests adding flags to commercial breaks to stop a viewer from changing channels until the adverts are over. The flags could also be recognised by digital video recorders, which would then disable the fast forward control while the ads are playing.