For poltical reasons we rarely see any air suppport (medical) here in Surrey...
But when I was in Sussex I used to try and pass any info such as wires or other hazards to the ASU - sensible compromise as the local, observed risks are notified to pilot but no risks added due the suggestion of possibly unsafe sites.
Even when based on a pilots perspective from the ground things look different from the air...
Having said that think there should be some basic helicopter awareness training given to anyone - police, ambulance, fire, etc - who may encounter helicopters, eg. approaching aircraft, dangers, etc.
PW