It appears to me that the accident wires were a long span over a valley without a clear line of towers or right of way. There is no mention of that span being marked on the surface.
There's some mention of charting wires in various accounts of this accident. Charts, NOTAMs, and METARs are all historical information and shouldn't be considered as definitive.
There's mention of failed verbal communication in various accounts, but no mention of a method of visual signals, like a "waveoff/abort".
P.S. Y'all can argue about stabilized, autopilot, multi-engine, day/night, IFR/VFR, 2 pilot crew, etc., all you want, but what works is well supported well trained pilot in reliable equipment allowed to work with minimal external pressures.