@Michele835 Yes, guests get reminders. Whether they pay attention to them or not is another story. I don't see anything wrong with sending a friendly message with a gentle reminder-"Hi XX, I noticed you haven't left a review and don't know if you're aware that this is last day you can leave one. I realize you may be busy, maybe you're traveling, but if there's any way you could take a few minutes to do so, we'd really appreciate it."
Of course, more than one reminder message would be intrusive. Some guests just don't bother.