  The search for the signature of non-thermal (so-called ``hot'') electrons in
illuminated plasmonic nanostructures requires a detailed understanding of the
non-equilibrium electron distribution under illumination, as well as a careful
design of the experimental system employed to distinguish non-thermal electrons
from thermal ones. Here, we provide a theory for using plasmonic molecular
junctions to achieve this goal. We show how non-thermal electrons can be
measured directly and separately from the unavoidable thermal response, and
discuss the relevance of our theory to recent experiments.
