I found Improving tagging of questions with [nearest-neighbor] and related tags addressing the issue exactly, but neither can I follow if there have been any changes made, nor, and more importantly, can I see changes in the tagging behavior.
As of right now there are 159 questions tagged nearest-neighbor and I assume, only by reading over the titles, that the correct usage of nearest-neighbor has not increased fundamentally to what @raphael counted 3 years ago. To be honest, I myself had been editing/adding the tags in the past to include nearest-neighbor where it is inappropriate, before I realized my mistake...
The nearest-neighbor tag, describing the common raster resampling algorithm, is frequently (and wrongly) used to tag questions about spatial relations between vector geometries, where proximity, nearest and/or knn is appropriate only.
Should we evaluate the possibility to change the tags and synonyms to a more intuitive naming/namespacing?