Good Job, Reel-Break!
I've been looking for something like this for a long time.
I've checked UL, not required.
I contacted AFC and AlFlex both about this; the answer was the same.
"The bushings, though not required, are supplied as an additional means of protection"
Good enough for me...I use 'em.
BX is AC Cable= Bushings always required
MC is MC Cable=Not required, but supplied for free.
You guys make your own decisions as to the value of your time.