Yea I was going to ask that actually. How to tell if it's a naked shirt if it only shows the person from waist up? Because for naked_shirt to qualify it has to be clear that only the shirt is worn with no other forms of attire.
There are 4 posts for naked_shirt bust (maybe more), and minus the Reisen pic, I'm asking how does the naked_shirt tag apply when we don't know if the person is wearing anything below? Edit: well, unless the artist said it as such I guess.
Well the norm is "tag what you see". If it's impossible to see if a bottom exists or doesn't, that rule is sort of moot. Tagging with either assumption (or with outside knowledge or intuition) is probably acceptable in this case.
After all, who's to say which case would be the default or expected case for a girl with an open shirt? Either way seems likely to me.