Locals tend to bring friends, family, laundry, parties....
I state "we no longer host local guests" at the top of our listing but it doesn't deter them from trying to book. I also have instant book on so if they DO end up booking, I use the fact that I have this statement in the listing as my "out" to cancel them penalty free. It's worked every time!
But honestly, I will still take them if the story is good - my bathroom is being gutted for a few days, my mom is having a 6 am surgery a block away at KUMed and we need a place to stay and rest during the day, my husband and I take a staycation twice a year and explore a new neighborhood.
21st birthdays, guests who are not friendly and forthcoming from the start, ones with brand new profiles do not get to stay and I just call AirBnB and decline or cancel them penalty-free.