OSM's been pretty hardcore about their no import policy because of accuracy issues in validation. They want to map these places themselves and don't want to trust others for accuracy, let alone the legal issues that come with importing data (ugh).
We, however are far more lenient (mostly because we can't afford to build a time machine to map the past ourselves).
On the other hand, Mike Migurski's Green Means Go [1] project is fantastic for figuring out where batch imports into OSM will be greeted with confetti and parades for filling out parts of the US without enough coverage to warrant anti-import protectionism.