@Rosa2878 I cannot find an actual Airbnb policy which states this.
But when experienced hosts tell you that guests can leave a review if they cancel within 24 hours before check-in, because they have had that happen, why would you call that into question?
Hosts aren't just guessing about it, they have experienced this. If you aren't open to learning from other hosts' experience, and don't believe them, then it's rather pointless to post on a discussiion forum.
I understand wanting to see an official written policy, but I can't seem to find one. There is wording about leaving a review if the host cancels, but not if the guest cancels.