Running steel cable or nets, instead of monofilament wire, is pretty much SOP for denying an area from rotorcraft. There's a pretty cool article on Wikipedia ab

Running steel cable or nets, instead of monofilament wire, is pretty much SOP for denying an area from rotorcraft. There's a pretty cool article on Wikipedia about prison escapes by helicopter [1] that explains how this is often implemented in high-security correctional facilities. [1] https://en.wikipedia.org/wiki/List_of_helicopter_prison_escapes https://en.wikipedia.org/wiki/List_of_helicopter_prison_esca...