As far as I know you currently still have to specify the policy.  It was, yes, intended that 'default' become the actual default.  I could have sworn there was an open issue for doing this, but I can't find it.  I remember having a conversation with someone who said they were going to work on getting it done, but unfortunately I don't remember who :(

I'm not very active in the python community currently so I can't really drive it, but it should definitely happen.