Sneaking orphan data into a review article

I find that it is not uncommon for me to run across a paper that is nominally a “review” article but yet contains data that have not been published anywhere else.
Have you ever seen such a thing? How common is it in your reading?
The next question is how you view the ethics of such a practice.
Ethics?
Well, the first issue is whether the data have been truly peer reviewed; because you may assume it is the intent of the authors that the data be cited. As if they were peer reviewed data like any other.