Supposed Universality of 1/3 Shot Noise Reduction

In coherent diffusive samples a shot noise reduction factor of 1/3 results from teh bimodal nature of the transmission probabilities. A reduction factor of 1/3 has also been found in the case of incoherent scattering, treated by the Boltzmann-Langevin equation. The occurrence of the same 1/3 in both cases has been celebrated by a number of investigators as universal. We elaborate on an earlier discussion, pointing out that the physics in the two cases is very different, and that the repeated occurrence of 1/3 is not a consequence of an underlying common mechanism. Therefore, it is a numerical coincidence. An appendix is oriented to a different topic, and evaluates adventurous device proposals.