This happens on the BBC (which is ad-free) & it drives me mad! E.g. Dragons' Den is clearly pre-formatted to be sold to commercial channels with ad breaks - there is about 20 mins of content in a 1 hour show w/ 40 mins of recaps and dramatic panning around the 'Den'.
Martha Stewarts cooking (show on ad free PBS) has a tacked on "Bonus Feature" at the end that seems to be just the right amount of time that it wouldn't be needed if they were showing ads.
I'd never clocked that, but all the BBC's nature programs have a 15 minute "making of" documentary at the end as well, which now you mention it must get cut for commercial networks.
Nova, Discovery, History Channel, Airline Disasters, etc. All of them (I view via YouTube / YT Download).
For Airline Disasters, skipping forward to 20 minutes skips most of the useless pre-accident crap with 5x replays of all critical moments. Annoying as fuck.
