It's important to leave an honest review, and be as specific as you can regarding the broken rules.
The 'end bit' of your review is really important (where you are asked the YES or NO question).
When you choose the NO, that guest can no longer use Instant Book, making their previous reviews visible to future Hosts. Overall, a poor review from one guest is lost amongst your positive ones, and you can put a cheery comment below it anyway. A poor review of the Guest will be a 'flashing light' to future Hosts.
Chin up !
Cheers, Charles
@Juliet514