I just reverted a bunch of tag wiki edits by a ~7k rep user that just copied somewhat meaningless information from Wikipedia into various previously-empty tag wikis.
I assume he simply didn't know that this is a bad idea. It would be nice if the site automatically searched e.g. for the first sentence in the wiki and excerpt and displayed a warning to the editor if there's a wikipedia result (or any other exact match). In case this is just a warning and not an error the same notice should be displayed to anyone reviewing the suggestion.