If you are sampling randomly, you can't go out and "pick a better spot"   That would make the information worthless.  The whole idea of random sampling is to get a large number of samples from RANDOM locations.    The large number of samples insures that any one sample location isn't going to skew the results. 

If the "field drive" is within the borders of the field, then it's part of the field and if it is randomly selected,  so be it.  If it's outside the borders, of the field I don't see how one could arrive at it based on directions from compliance imagery.