Avoiding loopy merges when cleaning up Place vocabularies with Taxonomy Manager

The key to preventing infinite loops in a Place vocabulary, which can be introduced while cleaning it up via Taxonomy Manager, is not to assume that just because something has the name of a country that it is a country.

Users have on occasion mistakenly put a town name in the country field and a country in the town field.

Now, I had already adapted taxonomy manager (via form_alter, without touching the its code, we did it the Drupal way!) to show this information provided by the Place module.

So it's really a simple matter before merging any terms to click on the term first, and see what "Level" it has -- Country, Province/State, Town/City.

Terms with incorrect levels should not be merged, but replaced on the nodes that use them (generally only one since one person makes the error)

So, key warning sign: Duplicate place term names mean that the same place name has been used on different levels. This is permitted so that Georgia, the country, doesn't conflict with Georgia, the state (for example). But if you see duplicates while trying to clean up via Taxonomy Manager, that's a pretty certain sign of user error, that could be compounded by admin error if you try to merge terms with the same name!

Resolution