If I were the owner, my response would be “no, kindly stay out of my business. If you have specific concerns about the behavior of one of my housemates, I’d be happy to address them.”
Why not focus on the behavior of the people living there, rather than the fact that the people happen to be unrelated by blood? Should someone not have the right to rent out rooms to ease economic hardship, assuming no overcrowding exists? What if I bought a house and decided to share it with some close friends who were all decent people?
Do I really need to get crap and possible litigation from nosy neighbors just because of an innocent lifestyle choice?
As long as they’re keeping things clean, relatively quiet, and following the precedent of occupancy being less than or equal to one plus 2x the number of bedrooms, it should be a private matter.