The question you need to ask is, on a case by case basis, "is this a mistagging".  In the case of something like "highway=pirmary" you can be reasonably sure that it's just a misspelling.  In the case of a rare type of memorial you can't be sure unless you check other sources (like the IWM's picture, which I've now linked to the object)
Whether there's a wiki page is irrelevant.  
Also if a tag is used by data consumers it is only common courtesy to let them know.
