Sure but the idea is that you don't try to find out who the author is, and if you recognize the author anyway, you decline the review. I review regularly and that's what I do whenever I recognize an author.
Not very often in a way that causes me to decline to review. What happens sometimes is that you have a suspicion but it's not definite. It could be one out of a dozen authors, or a newcomer you've never heard of. I'm in the humanities, however, things probably look different in the natural sciences.