Mmmm? I see your idea but what advantage will it be? It will not absolve the pilot of perfoming a proper site recce prior to making his approach and so he will land where he believes to be appropriate and safe. Also it is often impossible from the ground to see obstacles in the undershoot or departure for a site - obstacles that the pilot can see.
When I get the chance I talk to police officers, fire crews and ambulance staff and just tell them to stand with their back to the wind and not near wires!
If I get to a scene and fine someone standing with their arms up indicating a place to land I often just set it down where they are but if I choose not to land there, I always try and talk to them after about my decision, so that they don't feel they are wasting their time.