Two reasons, none of which hold any weight, caused me to write it like that:

- I wanted to see and be able to check that it was working in the nosetests you wrote
- I thought it would be nice to let the renderer know WHEN the legend was about to be drawn, however, it's clear that a renderer can take care of any legend tasks it wants to do within the `close_axes` method. 

I'll switch it and change the tests.