surely there's enough people with access so that leaking one country's numbers won't be enough to catch them?
For the audience that GAF attracts, NPD is much more prominent.
Not to mention, NPD has a very, very long history with GAF.
That same history...just isn't there with GfK. Yeah some GAF members have been posting GfK Chart-Track rankings for a while, and there are some people here on GAF who have access to the numbers, but it's just not the same.