But its not the job of the software developers to research and plan the wireless coverage of the location, its the job of the team planning the event.

Here in germany for big festivals every carrier places a truck with mounted wireless antenas nearby the event location to ensure a good wireless coverage. I dont know how it is in chicago, but for such an event the planners should have asked the big providers if they can do something to not have wireless outages. But maybe this would have costed them some money they wanted to spare.