Why is it that in every army recruitment video or army training sequence in every movie you see people training on the use of a zip line? So in the instances where one is invading a base that is a) lower in altitude b) connected to your current position via a sturdy cable and c) negligent enough to not watch said cable whatsoever so as to be unable to shoot the invader like so much a duck in a row, this is a viable mean of ingress. Might as well spend more time at the blowing up entire villages with a single explosive tipped arrow range for all the use it would be.