We are two friends who currently work at a catering company (no name is needed, many catering companies operate in similar fashions) and have an inside look into what happens in the kitchen after major events. Sometimes the extra food is given to staff members, and more often than not, the food is thrown away, on the spot.
Our idea is that there could be a company who comes to pick up the extra food immediately following the event and re-serves it to those in need at designated location. Those in need could receive an alert on their phones when the food is ready and being served, as event end times vary.
We would need to work with a health/food service professional to determine what food is safe/unsafe to re-serve.