Exactly. It's a *massive* grey area and it's much more an issue for public institutions than private individuals.That'd just being pedantic, capturing someone walking down their garden path at the edge of the frame (For example) is hardly branching somebody else's privacy or using CCTV irresponsibily
A private home owner who has been burgled in the past, putting up CCTV watching over their driveway whilst capturing a small amount of the street and pavement has *nothing* to worry about. If you read through the ICOs advice, they rarely categorically say something is illegal and even if it was - who is going to take you to court? They just try and advise people to not put CCTV up unless necessary to stop any potential complaints about harassment etc.
Bringing this back to the original mentioning of this issue - no police officer in the land, or court, would question the CCTV footage of someone being caught committing an offence, as long as it wasn't zoomed into their living room.