Earlier quoted context omitted.
Oh, did your banana have "CAT III Max 600V" stencilled on it? The $15 multimeter does. I suspect the cheap meter has about the same right to wear that label as the banana.
Does Sparkfun's product actually fail in 590V environments? That seems like a more serious concern tha branding.
Not that I'd like the CPSC anywhere near electronics, either. But given the amount of QA those meters probably (don't) receive and their intended market, Sparkfun should be responsible and either post their ongoing testing process, or probably just drop the rated voltage to 100V.