Maybe the answer to that George is to fly them in pairs or in flights. After all would you send an individual helicopter forward? With ano air or ground cover?
And don't helos have blind spots that limit vision? How about crew members, in flight, mounted or dismounteed using binoculars or other Vision Devices, like NVGs, CCDs, Thermal Imagers? It seems to me that all of the above can tend to produce the blinkered effect you are speaking about. Ins't the DS solution to keep in mind those limitations when assigning arcs of observation and fire and ensure that the entire area of interest is kept under observation?
From what I can gather in Iraq, the US Army re-evaluated their helo doctrine to keep attack helos behind the FEBA after that raid that basically saw an entire Helo Brigade shot up.