From what I've read, the Jujamcyn's will not allow Local One to work the Grinch so it will remain closed.
But let us not forget that Local One struck the Grinch (the SHOW), receiving much bad publicity for it. I find it odd that they "suddenly" reversed themselves. I think they knew that the Jujamcyns would not allow them to work the show, and hoped that the League would then be the butt of the bad publicity. I think both sides are game players, but I think Local One is the worse of the two. And it's now pretty much being reported that the League did not, in fact, walk away from yesterday's negotiations first - there was apparently some sort of rift between the head of IATSE (who wanted the union to accept what had been hammered out) and the head of Local One, who, from all reports, is an arrogant and disruptive person. He refused to accept and walked out.