I've recently noticed that some overzealous persons not only stared to remove zettai_ryouiki tags from the pictures with shorts, but also have changed description to wiki by adding the incorrect clause stating that "zettai ryouiki does not apply to characters that wear shorts"
Except it's not (no longer?) true.
From japanese wikipedia: https://ja.wikipedia.org/wiki/%E7%B5%B6%E5%AF%BE%E9%A0%98%E5%9F%9F
スカート、ショートパンツ などのボトムスとニーソックスを着用した際にできるボトムスとソックスの間の太ももの素肌が露出した部分を指す萌え用語。
Also, the post which drew my attention post #2922194
Ironically, here is the part from original anime https://www.youtube.com/watch?v=Z8bH4EndPEQ
Point is, sometimes even japanese ommit shorts with the official definition. But they don't have any problems neither doubts about ZR with shorts or other kind of short pants - as long as "forbidden" (erogenous) parts of body are still hidden (ie. buttocks, hips, vulva). And no, it's not "you can almost see but barely not" concept - because there would be no place for thighhighs in that. It's simply a "cloth-bare (allowed to expose) skin-cloth" concept.
And one more thing - changing the definition of tag without official discussion on the forum (only hiding it in subtopic like this http://danbooru.donmai.us/forum_topics/12251?page=30 where you had no chance to take part in the discussion unless you're actively following it) is criminal and can lead to disasters like this. I suppose it's only natural to expect that people who jumped the gun then and "cleaned" the tag take responsibility and reverse all the premature and in fact incorrect changes.