It is to my understanding that in the city of Shawnee, Kansas, a similar law was voted in to “protect tenants from exploitative landlords”. As for Springfield, the unrelated tenant cap is news to me as of yesterday. While it’s true that there are zones where this does not apply and therefore cannot be legally enforced, unfortunately there is only a handful of affordable 4BR rentals available and all of the ones that I have specifically searched for on zoning maps are located in R-SF zones. Luckily, you’re right, it doesn’t really seem like the city even acknowledges this law.