If I'm the NFL, my contracts going forward are going to deal with these issues. Don't sign the Franchise tender? No problem..., but there's a penalty the next year you do decide to play (or perhaps compensatory draft picks or some other boon for the team that didn't get to benefit from the tender).
Don't want to honor a signed contract? No problem, but there will be some sort of penalty IF your team doesn't agree to trade you. (for example, if the steelers didnt trade AB and he sat this year...). The steelers decided to pay AB rather than the other WRs we had at that time... Now AB gets to unilateral punish the steelers because he made a bad deal? Crazy.
I'm fine with some measure of guaranteed money, but its going not going to be 100%, and its going to come with major stipulations.
Bottom Line - both sides need to honor their contracts AS WRITTEN, or be penalized... you know, like real life.