It does get annoying though, if he's taking up a park.
I used to live in an inner city unit with about 10 spots for 16 units, plus one guest park. I don't know how many times I'd come home from work and there'd be someone parked in my (clearly lablelled residents only unit #1) spot. One time I couldn't get to work because some idiot had parked BEHIND my car and I had to go hunting for the owner. In an area with virtually zero street parking, having to park a block away from home when you've got shopping and a small child is REALLY ANNOYING. I did that once and just parked in someone else's spot after that. Serious downside of inner city living where you have open carports not lockable spaces.
When I had the carpets cleaned on exit, the carpet cleaner guy had to park on the median strip (which was more than big enough) and being a snooty suburb, he was reported to council in the time he was there. And council actually sent out an inspector - all in the time it took to clean 2 rooms. This suburb has a reputation for serious busybody interfering development blocking residents, anyone in Adelaide should be able to pick it.
Definitely talk to the owner of the car though, once he's off the street there really isn't a higher body to whinge to.