Sidewalk Smokers

I live in Massachusetts and I rent from my grandmother. She lives in the upstairs apartment and I live downstairs. Our neighbors across the street are smokers and will come over to our side, sit on our steps and smoke. They’re loud, leave the cigarette butts on the ground and have been blatantly rude when asked to do it on their side of the street. The only excuse they have is “we’re on the sidewalk, you can’t tell us to leave.”. Is there anything I can do in order to get them to stop? I’ve thought about setting up a sprinkler system to go off at random times so they’ll get wet whenever they smoke but my grandmother is concerned about the drama that’ll occur.