Hi Roger!
For historical reference...somehow I don't think you would ever be questioned about your locations ala the DXpeditions by Don Miller in the 1960's. Technology has come too far...
Several have reported to me that some of my grid-boundary expedition QSL cards were questioned by VUCC card checkers, even with the GPS latitude/longitude readout printed on the card. I have never been contacted by ARRL to provide any documentation regarding my grid expeditions, but there's always a first time for that in the future. I prefer to be safe and have all of that with me, than not have it for the one time I may be called upon to provide the documentation.
As for Don Miller, yes - I am familiar with his escapades. When the VUCC rules were updated in late 2008 to coincide with the new Fred Fish award for 6m, I made sure to understand them and comply with them for anything I did after that point. I don't want other satellite operators to lose credit for grids they worked me in and have my cards for.
73!
Patrick WD9EWK/VA7EWK http://www.wd9ewk.net/