Most guests have no idea how star ratings affect hosts, nor that one 4 star rating could cost the host their hard-earned Superhost status. Airbnb tells them that 4*s means good. They don't tell them that we get penalized for less than 5* ratings, whether it's losing or not acheiving Superhost, or receiving warning messages from Airbnb to pull up your socks.
Since I host in my home, I have lots of interaction with my guests and lots of opportunity to educate them as to how Airbnb grades hosts. Most are shocked at how punitive it is. Of course, I don't tell them to leave me a 5* rating. But I've found by just letting them know how it works, that 5*s on Airbnb doesn't mean perfect, but means they were pleased, had a good stay, and that the listing info was accurate, leads to them all leaving 5* reviews.
For those who don't have much interaction with guests, this info can be written out and left in the unit.
Most guests have no wish to tank a host's ratings, or have a host penalized, they simply aren't aware of how Airbnb rates us.