Interesting point B&B, and the answer, from me, is that not only do I not have a clue, but I hadn't even given it a thought.
I'd guess it isn't open ended though. That said, I'd guess a few SL clubs (all?) wouldn't have found it too easy to fund that sort of trip, but I'm confident (?) the RFL, who organised the whole shebang, will have it all organised under some kind of contingency (aka cunning?) plan. I'd suspect a few championship clubs would be on the phone to the RFL, or more likely hammering on the Red Hall door, if nothing really is down in writing.