Agreed 00000 is not black, but the reflection is not from the backing layer but from the transparent glass.

if the glass’ reflection is greater than the emissivity of the actual screen, isn't the screen black for all purposes? After all, even if you painted the back of a pane of glass with vantablack you would still have a reflection of the glass!

This reminds me of some difficulty I've encountered with printing computer images. #000000 often comes out as just-off-black. Computers use RGB while printing uses CMYK, with the K meaning "black". So in some places, like Vistaprint, I would have to specifically set K to a max value to make it look right

...this is a good point!