In my experience and training, I'm under the impression that a diminished triad isn't listed in a chord chart unless it is considered the Diminished 7th chord function. While there may be different functions for diminished chords, in my experience, the Locrian mode is used for the m7(b5) chord, not the diminished chord.
I say that the min7(b5) chord isn't to be hidden behind the "Diminished Triad" label. The diminished chord has a bb7, and the min7(b5) doesn't include that. If you're using Locrian over the diminished triad, it's a mislabeled min7(b5) chord, no?