They will probably offer their currency at a discount to incentivise to take it anyway! Of course, that promise is only credible if they aren't near bankruptcy

They will probably offer their currency at a discount to incentivise to take it anyway! Of course, that promise is only credible if they aren't near bankruptcy anyway, so I suspect that specific rule won't change much in how the game is played. (Things like selling shares in one's properties, on the other hand, makes it possible for the game to go on for a really long time. Some games turn into complicated interlocked arrangements where nobody wants anyone else to fail lest the whole thing comes tumbling down -- much like in the real world. At that point the game is less about winning and more about finessing your way around a financial system.)