I saw this on Tumblr a few days ago, and can happily report that it does seem to work. The test case was searching for images of "serval" (a kind of wild cat),

I saw this on Tumblr a few days ago, and can happily report that it does seem to work. The test case was searching for images of "serval" (a kind of wild cat), and the addition did indeed clean up the results. Somebody else had suggested adding "-AI" instead, but AFAICT it did nothing. Kind of sad that Google can't/won't address this themselves in any way that seems to make a dent.