I have found that most often sheaths are most often potrayed as detached_sheath, however many are not tagged as neither attached nor detached, and as such it's simply not enough to specify -detached_sheath, i.e. tagging as detached is not effective.
As a mostly/entirely attached sheath seems to be in the minority, I suggest detached_sheath be used more readily. I have created a wiki page and the thumbnails are all really good examples of what I mean, along with those currebtly tagged.
Lastly, I'm not familiar with the moderation, so delete if this is out of place.