Actually, come to think of it, I think there's a pretty good case for just calling:
1. Despite what I said earlier, I think there's some
extra chance that rory will overcall.
2. song is rarely bluffing
, but the few times he is, we gain from not pushing him off his bluff quite yet.
3. If song and/or rory has a real hand, we're getting all our money in anyway.
4. If rory has a real hand that he'll call a push with now, but a scarecard comes off on the river (e.g. a T), the pot ought to be big enough for him to make a crying call anyway. I don't think he'll fold two-pair often.
So what we need to weight is #4 vs. #2. Will he make a big laydown the times the river brings a scarecard? Or is he always committed to a showdown? If he's committed to a showdown, I think we can just as well call here and pick up a few extra chips on average the times he's bluffing.