I am irritated that due the usual parsimony and short sightedness HMG is not protecting my frequent overhead visitors (and my power supply (n.b. this last is an attempt at humour)). Oddly though I haven't heard any wokka-wokkaring for some days.
Apologies if this is mentioned above but apparently the Canuck Chinook Fs have wire stike protection fitted, so its not unknown on H-47s. See page 14 of this:
A 2010 Industry Briefing given by the Canadian Director Air Requirements
The cancelled HH-47 CSAR-X had WSPS (Wire Strike Protection System) included in its requirements.
Given the successful history of WSPS on the US Army's light to medium aircraft it should beggar belief that it hasn't been rolled out generally across military RW fleets with low level over land as part of their operating profile, Unfortunately history teaches us there will have to be multiple fatalities before anything is done.
This 2008 study makes interesting reading.
FAA - SAFETY STUDY OF WIRE STRIKE DEVICES INSTALLED ON CIVIL AND MILITARY HELICOPTERS