When, in this age of “graffiti cool” and “street art chic,” has tagging someone else’s property been a matter of national concern? When that property happens to be Air Force One. A mysterious online film began to circulate on the web showing hip hop outfitter Marc Ecko taking a spray paint can to the President’s 747. It was reported on across cable news, particularly on political networks, where pundits were astonished that anyone could have gotten so close to the president’s plane — for the rebellious purpose of spraying graffiti on it.