@Linda108, interesting question you brought up! Let's see what @Cristina-And-Daniel0 have to say....
I found that just about all hosts leave up positive reviews, even when they had a bad experience!
So really, I am curious, have you ever seen a review on a guest that would make you hesitate?
A tip off that someone might be difficult could be if that person has no reviews at all, which is what I do with guests I didn't particularly care for, and sure enough, when I go back to their profile there is hardly anything there..
Also guests that I hardly met and who don't leave a review for us, I don't review them. Not that they did anything bad, then I would let it be known!
And most of the brand new Airbnb members, particularly the younger ones, don't bother writing reviews, and I don't feel like prompting them - it all becomes a more and more anonymous process, that is definitely the trend....