What is the appropriate way to handle these kinds of edit reviews?
The edit claims that some facet of an answer is wrong and proposes replacing the "incorrect" part with the correct information. The change isn't enough to warrant an additional answer and a comment is transient. Is the appropriate edit to replace the information or add the correction as supplemental information (if it should be done at all)? Also, does it make a difference in how the edit should be done whether the edit includes a citation validating the correction? Does it matter whether the answer has been accepted and/or upvoted?
An old answer. The edit claims that the answer is no longer correct (for example, because the current version of the software is different). Should the edit be in the form of supplementary information that refers to the newer version of the software? Should some form of citation be required?
An edit like 1 or 2 is proposed by an anonymous user who provides no citation and the reviewer cannot readily validate the information. Should unattributed substantive edits be accepted?
Should the reviewer be in the position of "ruling on" substantive changes of this nature? Answers get the review and scrutiny of the community and that process is bypassed when these kinds of changes are done as edits.
Is there a mechanism to provide a comment to the user proposing an edit to explain why an edit is rejected or to request additional information, substantiation, or changes to the edit that only they would have the knowledge to make?
Edit: There seems to be a grey area. On the Tour page and the Help pages, edits are described as: "to correct minor mistakes or add addendums / updates as the post ages" (in addition to grammar and spelling mistakes). For community wiki posts: "...others will edit them to keep them up to date, to add useful information,...". So it appears that community wiki posts actively invite at least updates to keep them current and expansion, while regular posts have a more restrained policy.
However, it looks like addendums and updates for currency, even on regular posts, are part of the plan, and correcting "minor mistakes" may be somewhat of a judgement call. Can anyone elaborate on the scope of what is appropriate for "correcting minor mistakes" within this context?
I assume, as Psycogeek suggests, that the default position on any proposed edit of this nature on a non-community wiki post is to reject or skip unless the person proposing the edit substantiates the validity of the change (or you can verify it), and that addendum is preferable to modification. And I agree with him on the importance of keeping visible on non-community wiki posts what are the original author's words and what are not when these kinds of edits are made.