@gdnrbob
Sometimes this is legitimate, and in the past, I could see that it was due to poor design tools.
Like in the early Genesis era. Damn, some of those crossovers are horrible in terms of impedance, but I can see how they got there due to manual trial and error. Attempts to get a certain sound out of the speaker, and not having very easy tools to help you optimize frequency AND impedance at the same time.
I can also see it with something like the giant Apogee true-ribbon speakers. The very technology caused 1 Ohm impedance, but with dynamic systems, I scratch my head.