... I would appreciate comments before we produce this in numbers...
Well black will not get as filthy looking as quickly as white.
I like the idea of it snapping together around the cable so it can live there permanently. Maybe include some tape or velcro so it even lives in the same spot with the same rotation orientation around the cable.
The big flat surface is a good place for your big ole' name and or logo. Also to sell ad space and or licencing car makers, cable makers, charger box makers, or to any one of a million makers of promotional marketing giveaways.
I hope they are being made in the US