Setting default region from credentials file

[TimWSpence]

I just spent quite a while with a colleague trying to figure out why the aws shell wasn't honouring the default region that we'd set in ~/.aws/config It turns out that somehow she had got a line in her ~/.aws/credentials setting the default region to something else and this setting was being preferred. This seems like a bug, unless it is the intended behaviour that all files in ~/.aws are valid locations for default settings?