don't know but here is how I analyze this
 

Let me start this by saying I don't know either from experience or from hard rules. Here is the way I think about the situation you posited -- due to operational issue of carrier and no fault of your own, you miss the flight.

I think of an analogy to help me. Imagine you booked a very desireable reward flight and the connection is missed because your first segment is late late late.

If there is no award inventory for the next month on your next leg, would it be reasonable for the airline to make you sit in that city for 30 days until the next exact fare bucket opens up? On the other hand, would they look for a reasonable routing, perhaps looking for a differnt bucket like Y or F and get you onward?

Based on all the experiences I have had with airlines, the second case is much more likely. Remember, I am not talking about customer requested changes or customer no-shows, but that operational issues cause you to miss the booked segment.

Going with the logic of the analogy, I would suspect that the airline would look for a reasonable way to get you to your next destination and not insist that you conform exactly to the flight, date and routing of the ticket -- this is not a voluntary change on your part. They might have to use some irregular operations ticketing magic, including the code for disrupted flights, if the systems won't allow the extra segments to be directly entered with your eticket, but they will find a way to get you moving forward as soon as a seat is found. Might be a case of downgrade versus longer wait, but in that case they would likely discuss it with you first.

...............

That does sound like a very reasonable way for someone to approach looking at this.

But I also realize that sometimes "reasonable" doesn't always apply. For example, when my current boss added my section to her control, she complained to me about the number of days off I had switched in the previous year. I explained to her that all of those changes had been accomodations I made for the convenience of the agency, not my own. She said it didn't matter, that I was not to do that anymore; so I confirmed with her that I would inform the other department that from now on they would have to alter their scheduling to conform to my schedule if they really wanted me to be available for those events. (She also had refused to authorize my getting a pager, cell phone nor blackberry--which actually suits me fine [which is why I don't push it]as I don't need the headache of the three other departments who would really like me to have at least one of those devices so they can get a hold of me more often). [I have said that the only thing she would give me is a "raspberry"--reference to a rude sound in American culture; hopefully not something cruder in another... ;) ]

Thanks again everyone,

Steve