Lucklily this problems doesnt exist here, every vehicle has a precise leaflet with all the technical details with must be with the vehicle at all times (I assume in order to make the excuse "I didnt know I was overloading" invalid).
Therefore I know that my Honda CBF 600 has a 197kg (~435 lb) carrying capacity, about the same for the KTM Duke 390 I currently fancy.
While obviously higher than the capacity of the Zero or the Brammo it is still not a lot, I e.g. weight about 115kg with boots, helmet etc, which gives only 82kg for a fully protected passenger - not an awful lot, it keeps most of my male friends away and sometimes serves as a excuse to avoid carrying someone
. Keep in mind this is an explicit touring vehicle!
One wonders why the limit is so low. Is it the frame? The tires (which would explain the low general level on all known bikes)? The suspension (maybe fixable/modable)? The very conservative estimation by the manufacturer in order to avoid any problems and/or legal responsibility?
I would like to hear from Brian how they got their numbers for the GVWR of the Empulse. Is it a conservative educated guess? Were you limited by some bought subcomponent? I cant possibly imagine one would design a frame with such low carrying capacity in mind.