Guest with trips but no reviews

[Terrill0]

I’ve noticed an uptick of guests with trips who have no reviews. The most recent guest has 3 trips but no reviews! I’m super confused. Up until this year I dutifully reviewed every guest. This year I’ve declined to review 2. 
I don’t understand how these recent guests have not been reviewed for ANY of their trips. When I have declined to review a guest it’s for a variety of reasons usually something about the trip was off and maybe there was an issue but no damage, the guest is essentially fine: there is no reason to ding them.  

My listing is set for instabook which the guest cannot use because they have no reviews? 
this most recent request comes from someone who is clearly a kind person who has filled out their profile with interests, and requested the booking respectfully.

are hosts just not reviewing guests for no good reason?

[Patricia2526]

Hi @Terrill0 

 Hosts may not have left reviews for these guests. This can happen if the host forgets, is too busy, or chooses not to leave a reviews.