FlickrExport for Aperture (3.0.0b25) doesn't seem to be ignoring the tags/keywords that have been set to be ignored when uploading. Even though I have my top-level keywords (and a few second and third level) like 'Hardware', 'Photo specs', and so on in the 'ignore these' field (I forget the exact nomenclature, Aperture's busy uploading right now), they keep appearing on Flickr.
Should exported tags match keyword in more properties?
I exported some photos from Aperture and stripped out some of the keywords so that they would not become Aperture tags. Although the tags reflected the changes (the ones I had stripped out were removed) when I went into 'more properties' all of the original keywords were still listed.