Apparently fan warning cards handed out by stadium personnel are a thing now. The latest such card comes, however, not for swearing, but standing too much at the recent Seahawks-49ers game in San Francisco.
The offender has responded with #FortyWhiners, but personally I side with the team on this one. Nothing's more annoying than people who stand up with the rest of the crowd for certain plays then forget to sit back down.
I'm not sure, though, why the Niners put the fan support text messaging protocol on the bottom of the offender's card. That seems like an easy recipe for a false accusation motivated by revenge.