You're not exactly by yourself in an NFL stadium. If you shout it at a player, odds a good someone nearby will hear it too.
The point here is that a player is making the accusation. How are you going to show real proof that fan xyz was calling a player, on the field, something racist? As you said, your not exactly alone in a stadium.
The other issue you could possibly have is being reported by a random person for no good reason. This happened with a similar program they adopted here in NM for drunk driving. They asked people to report suspected drunk drivers and the cops would pull you over if they saw you. What we ended up with were a lot of HS Girls reporting people they didn't like for whatever reason.
Lastly, what is going to happen if black people use racial language, which we know happens all the time, with other black people? How do you manage that?
I just think this is going to be really hard to make work.
