I would tell them, our neighbour across the road used to have their bf park his car right opposite our driveway which made it almost impossible to get out of our driveway (which only has a single lane crossover as per council). so i told one of them and it stopped happening.
but have another neighbour a few houses up who gets her visitors to park on our nature strip which urks me as we dont want our lawn killed or ground compacted like it is at her place.

