Which is the most baffling thing.
I guess the idea is that parking enforcers don't have to start knocking on doors to ask if that car is "allowed" to be there? I can't think of any other reason for that to be on the books.
Yes that's why. I recall a case in West Roxbury where a woman used to always park in front of her "storage" garage that had the door at the sidewalk's edge. A neighbor kept calling parking enforcement on her (out of spite I'm told) and there was nothing they could do. They couldn't dismiss the tickets because the city's rules and regulations were clear that you can never block a driveway. Most driveway blocking enforcement is complaint based anyway though, so many people, especially in the outer neighborhoods, tend to risk it.