If its any consolation, I find SMS and telephone to be remarkably robust in these situations. In college during football games, the campus population would swell to probably 200k people within a few square miles each with a cell phone in a pocket. 3g and LTE would be worthless. Campus area wifi would be worthless. The only thing that would work is shutting all that off your phone and resorting to SMS and calling people over EDGE, but it worked flawlessly even with all the people stressing out a handful of towers at once.