The image tag Cosplayer typically implies the tag Cosplay, however Cosplay (dressing up as a character) does not always imply Cosplayer (a specific person that often dresses up as a character). Especially now that we let machines tag all the posts, you can get just realistic styles of a character tagged as Cosplay. If someone blocks Cosplayer because they don't want to see images of realistic people, then the system is currently set up so it will block all images with tag Cosplay as well. This can negatively impact their ability to view and discover content that is a) mistagged as Cosplay and b) may involve characters cosplaying as other characters but no actual "real" looking cosplayers.

Please prevent hidden tags partial matching at least in this case, if not in general, as this implementation is probably unintuitive to most people and can lead to all sorts of edge cases like cosplay-cosplayer