That is correct, it uses both the coordinates and places fields (see more about those here https://dev.twitter.com/docs/platform-objects/tweets ). There were actually substantially less before adding the code to handle "place". Most tweets that are tagged with a place and not specific coordinates use a bounding box which I've handled by just dropping the pin in the middle of the box.
Also, here is a nice nugget of wisdom from Nigeria: "Fuck, don't give a fuck, don't get fucked over. 3 rules of life."