In TV broadcasts of football matches (soccer matches) there are often long displays along the side of the football field that show advertisements. I guess that these displays are made up of electronic lamps, but in the future it might be possible (albeit technically very difficult) to add the advertisements by just post-processing the TV photo in a computer. In this way TV companies could broadcast international football matches with localized advertisement, for instance with one type of advertisement per country.
Do you know of any examples from TV broadcasts of sport events, where image post-processing have altered the TV photo to adjust for different advertisements?