The best example is sporting events. I mentioned half time in the Cup Final in another comment: there's a referee-determined amount of injury time added to each half of the game, then that is subject to the ref (who is, as is required by the job, blind) bothering to check his watch. It's impossible to point to a given five minute window when the game will end.

And yes, British TV is pretty different, at least on the main channels. Over-running programmes will push everything else out to start later, rather than simply starting five minutes in.

TV shows - even in the USA - start all over the place, they are absolutely not 'clocklike' at all. So bad even TiVo has a hard time getting it right.