Many journals sometimes publish Festschriften, i.e. special issues in honor of a distinguished (but still alive) researcher in their field. Articles for such issues are typically invited articles by other groups in the same field, and current and former collaborators of the researcher honored.
A colleague told me that such articles are peer-reviewed, much in the same way regular papers are. I somewhat suspect that this might not be entirely true, and that the standards used by the editor (and even reviewers, if they are aware of the context) are lower for these special issue invited papers.
A quote on Wikipedia (from one Endel Tulving) seems to agree with me:
a Festschrift frequently enough also serves as a convenient place in which those who are invited to contribute find a permanent resting place for their otherwise unpublishable or at least difficult-to-publish papers
So, my questions are: in your experience, are reviewers given a hint by the editor that the paper they review is intended for a special issue? and is the review process and editorial decisions typically as strict as they would be for a regular paper?