The Raiders are well within their rights to make Milford sit out the season if he doesn't show up for training (No point arguing about a get our clause that I know nothing about). But at the same time, if he does show, I believe the NRL should step in if the Raiders f**k Milford over by storing him in the Reggie's with no intention of playing him. It's not fair on the player, just like its unfair on the club if the player stops training.
How the NRL could do anything is questionable (the Raiders would simply say it's their job to select the side they want on the paddock), but stifling a players talent just because he doesn't want to play the following season is just petty. Clubs need to realise that it's a professional game and players will change clubs.