I don't know if this is just a me thing or not so I'm posting here for opinion.
If you were to go to someone's house who you know has two cars, one of which is not on the drive when you arrive, would you park on there without the person telling you to? As in, would you think "the other car might arrive while I'm there and want to park on the drive" or would you not give it any thought? For context, there is on street parking right outside of the house.
DP's barber and our cleaner do this and it's really irritating when I/DP have only popped out to the shop.
YABU - I'd park on the drive because why should I have to park on the road
YANBU - I would assume the other car might be coming back while I was there and would leave the space for them