I agree Ron. Often you have IR in another city entirely working out of a nice office. While the Geo is out in the field at times and or a drilling site or a coreshack with gunboots on..........LOL It is my guess that he too is the one with the Lab on his speed dial!!
IMHO If all core had visible mineralization it would be easy, Heck why not walk around looking at logging road cuts in hillsides. I agree that it all gets a good look as it is pulled out of the ground. It must get tot he point where area drillers start to have a good eye as well. But as you mentioned, when you get the finer stuff in the PPM or PPB or for example, a low grade nickel at 0.20% in ore that came thru a "halo" zone, I would say that most core has to be sent in.
Lastly, there is infill, definition, and exploratory drilling, I bet they are treated differently in each case.