To be honest I thought "trigger warning" was the legitimate term to use.
Not that I ever give enough of a damn to use it myself, so I wouldn't really know. :P
No its just the way its used that makes it look bad.
Like Tumblr users will use it as an excuse to justify stupid things. Recently a friend of mine got a message on tumblr asking her to tag all her pictures that had faces in them as "TW (trigger warning) : Faces" or something like that because she had a fear of faces and wanted to block any image that had a face in it. Its ridiculous
They could have just said Warning and been perfectly fine.
Someone on the Grumps apparently uses it. :P
Arin