If the presence of a character is only implicated, it doesn't count.
Well if you look at the results for both, then despite them being supposed to be equivalent, there's an extreme schism there.
A single pussy doesn't really make any image tagged with 1girl, all of those actually feature a girl to a reasonable decree, and yet countless images with merely a penis are tagged 1boy. Sometimes even just an arm. And we're not supposed to tag by context, but by visuals, and even with a penis present, futanari exists, or also newhalf, which would too be 1other. 1other generally would be the fallback here if the person is only implied/indeterminate.
I suppose I am not even so much looking for discussion here as the wiki pages and the issue are pretty clear. If no one disagrees then maybe in a week or two, or a month I'll edit the wikis to be much clearer and re-tag the offending images, at least a bulk of the newer ones.