Perhaps I'm in the wrong area. It wouldn't be the first time. I wish there was a better review system. I understand the concept for not letting anyone see a review until after 14 days or after both reviews have been posted. I can honestly say that most of the reviews that I have received in my 9 years of hosting are 5 stars across the board. The exceptions are those few people that have nothing better to do than complain, or have standards so high that they are unattainable and there have only been a handful of those. I just had a review from one of the high standards type. I'm not particularly picky about things when I give a review. I overlook crumbs on the counter, full garbage cans, a dirty stove top and so on. Hey, the place was just lived in, and I don't expect them to clean it up for the next guests. That's my job. My problem is the unknown. I gave my last guest 5 stars across the board. Their review was posted before mine was. I submitted my review and then checked their review. My draw dropped. They gave me a three for cleanliness, a three for accuracy, and a three for value. In the review, they complained about a shower drain that wasn't working well. That's true, it wasn't, but I didn't know that, until the next guest told me. I fixed the problem immediately. Got 5 stars across the board from him. The point is, she didn't communicate with me about the drain. In fact, she didn't communicate with me about anything, so I naturally assumed that everything was fine. Now to the point. I didn't know that she had a problem. She didn't communicate. Giving her a 2 for communication would have been very appropriate, but she got a 5 because I had to make an assumption. Future hosts will never know that she doesn't communicate, or that she has standards that are much too high. I think that the rating system needs to be looked at. If nothing else, they should require guests to explain their reasoning for giving a rating of 3 or less. There's a response window for that, but it's not required. At least then, a host would know why they received the rating that they did, and then they would be able to respond to it, in their defense, in the Write A Response window that shows up directly below the guests review.
When you say the guest did not communicate about the problem with the drain, do you check in on guests to ask if everything is going well with their stay and if there is anything that they need? If not, then it may be a good idea.
Of course, you still get guests who say everything is great, or even 'perfect', and then complain later in their review. Like you said, some people just like to complain and are going to do so regardless, but sometimes it helps to prompt people so that, if there is an issue, you have an opportunity to resolve it.
I prefer not to disturb my guests. I will do as you suggested, but only if the opportunity presents itself. I leave a hand written note for guests on the kitchen counter, along with a welcome book. Included in that note, is my phone number with a statement telling them to contact me if they have any needs or concerns. Thanks for you input.