Originally Posted by Neil S
I would have thought that most if not all speakers with separate tweeters and woofers would have a passive crossover network inside?
For there to be a benefit from reduced impedance of the cable, the high-pass and low-pass terminals on the back of the speaker would have to be connected to each other internally, bringing us back to square one

Thanks for the input guys!

Neil.
Neil, correct there IS a crossover network inside all bi-wire loudspeakers but crucially the crossover is designed as "two halves" on the same curcuit board, and you (electricaly) split the two halves when you remove the EXTERNAL link bars/pins.
Example with the link pins (gold plated bars) in place: