This question could be better worded. Since the right to protest is protected by the 1st Amendment,  the "consequences" would have to come from the private employers. Should the NFL or team owners have sanctions for failure to stand during the playing of the National Anthem? As employers, the NFL and team owners could fire players for failing to follow rules (if they're in place) such as standing for the National Anthem. There could also be loopholes on religious, moral, or contractual grounds. In short, consequences, if any, are in the hands of the organizations. Perhaps a better wording would be: Should we, the public, pressure the NFL and team owners to require all players and staff to stand during the playing of our National Anthem? If yes, then should those who fail to abide be fired? The public could apply pressure in different ways, e.g., boycotting games (live and broadcast), boycotting sponsors of games, public demonstrations, op-eds.