Nflpa will lose.
You can't negotiate a contract with the NFL, then once you start cashing game checks, not live up to your end of the agreement.
Nope, The NFLPA would win, and win easily. Marshawn IS living up to his end of the agreement. He's making himself available.
Players – Players must be available to the media following every game and regularly during the practice week as required under league rules and their contracts and as noted above. It is not permissible for any player or any group of players to boycott the media. Star players, or other players with unusually heavy media demands, must be available to the media that regularly cover their teams
at least once during the practice week in addition to their required post-game media availability.
This applies to a maximum of one or two players per team only. The minimum for such players does not include other required media obligations such as visiting team conference calls, network production meetings, and national media interviews arranged by the team.
All NFL players,
upon request of their club public relations director, are required to participate in weekly conference calls with the media from the opposing team’s city. While a player is encouraged to be available for this call every time he is requested
by his club public relations director, no player is required to do more than five such opposing team/media conference calls each regular season. No player, however, can refuse to participate in the weekly media conference call during the playoffs.