In the park where I used to live there was no street parking because the streets were very narrow. My neighbors were usually very considerate; my neighbors across the street was part of a large extended family, and they often had cookouts in the summer. Because there was so little guest parking I would be asked if I cared if someone parked in my (very long) driveway behind my car. Normally it wasn't a problem, and if I was home they'd bring me some food. However, I made it clear that they had to ask first, because I didn't feel I should have to hunt someone down to move their car if I needed to leave. On only one occasion someone didn't ask first, and when I hunted them down I told them that if it happened again they'd lose their parking privileges. It never happened again until I moved.
Aside from this, the only other time I got blocked trying to park was one day when I got home, and a police car was parked in front of my driveway. If the officer had been there on business I'd have parked somewhere else, but he was standing not 10 feet away, chatting with the manager. He tried to wave me past, but I told him it was my driveway he was blocking, and he immediately moved his vehicle.
If someone parked on the street in this mobile home park and wasn't unloading groceries or furniture or something similar, they'd get an immediate warning. Our managers were nice people, but because the streets were so narrow the park would be hit with a huge fine if an emergency vehicle couldn't get through (or so I was told when I moved in), so the no street parking rule was strictly enforced.