Minor Plot hole
In the first movie (and book), the district members can get extra food by submitting more entries into the Hunger Games "raffle" - increasing their chances of getting drafted... unless the whole district agrees that EVERY district member puts in extra entries, thus getting more food for everyone without increasing the risk of getting drafted for any specific individual. I guess they don't teach them math (or common sense) in the districts.
The rich kids would never agree to do it. Yes everyone would have an equal chance to get picked. But the rich doesnt want that they want to have a lower odds so they never get picked. Thats why the poor and rich hate each other Gale made that clear in the book