Exactly that - our neighbours have a driveway that fits 3 cars at a push in one long line, so you have to move cars around if you want to get on and off the drive, same as ours. Since they moved in they put one car on the drive and leave the other on the road all the time. We're on a new estate where cars aren't meant to be parked on the road at all as it's pretty busy round here. Life's too short to be totally bothered by it but I don't see why they can't use the drive as they're parked on a T junction causing a small obstruction. I believe they do it to save time swapping cars round. Would you do the same thing? I only ask as we've always just moved the cars round 😅