I have a question regarding the removal of GNS tags. Do they not serve any purpose, and so is it valid to remove them in general or are there conditions for when to do it? 

It's just a hunch of mine but, I thought that maybe they could prevent future imports from creating duplicate data, so thus far I have not been removing them; maybe you know something I don't. Then again, the place names and source date tags probably should suffice to allow for prevention of duplication.
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            Published using OSMCha: https://osmcha.org/changesets/170431193
            