JimmyT here, Tonto
I think the point is that there has to be a legally binding resolution about who is responsible for the ongoing maintenance of the cable when it passes through common property. Normally pipes and wires that pass through CP would be OC responsibility but they may expect the owner to agree that if there's a problem in the future it's the individual problem and not theirs. Either way, it needs a special resolution so that everything is clear should there be a problem in the future.