Short-time events at locations like major sports stadiums, arenas, or concert venues unexpectedly have low results. There are many factors contributing to this, for example, patrons are not spending as much time on their mobile apps. The biggest factor is the mobile phone carriers themselves. With tens of thousands of people congregating in a relatively small area, mobile phone usage causes congestion that could cripple mobile networks. The venue typically awards a contract to a specific carrier to back-haul the mobile traffic out of the venue to the closest cellular carrier POP (point of presence). In this case, many of the mobile device locations are recorded as miles away from the venue.
In 2001 after 9/11, Homeland Security passed a law where any venue with over 10k devices have to reroute their cell traffic in order to maintain the ability for people to call 911 in case of emergency. One of the downsides of that is that the rerouting hinders our ability to capture devices in a location with over 10k devices for that timeframe. What you can do instead, is to target parking lots and businesses you think users might have been to. In this case, we recommend targeting bars and restaurants surrounding the event center.