@Janice146 Do you explain to your guests how a 4* review affects hosts? Because if you don't, you can't fault the guests- Airbnb tells guests that 4*s means Good, they think they are leaving a good review, they have no idea that a 4* overall can lead you to lose Superhost or even get delisted. If you explain it to them and they still leave 4*s, that's another story.
But I would never block a guest who was simply unaware. And they don't get aware unless hosts explain it. It's not their fault that Airbnb leads them to believe they're giving a good star rating. Most guests, especially someone who wants to come back, have no desire to harm the host.
One of the first guests I explained the rating system from the host's end to, was a super great gal who had stayed at lots of Airbnbs. She said "OMG, seriously? I feel terrible now- I gave my last two stays a 4* Overall, and the places were fine and the hosts were nice, I'd definitely stay there again, I had no idea! Why does Airbnb lie to guests? They tell us 4* means good, then they punish you guys for it?"