Firstly, I regret that the title of the Topic here should probably more accurately have been something relating to PECKING ORDER DISCLOSURE REQUIREMENT.
And, no, I wouldn't give up my seat to someone who checked in earlier than I did, unless there were a REQUIREMENT, to be followed uniformely by all, that they do the same, in some reasonable and logical order. After reading this thread, I should have made it clearer that TIME OF CHECK IN, was just an example of some NON-random, NON-partial method of POSSIBLY determing priority. I admit I still can't think of any way that's truly fair to everyone to determine who should get PRIOIRTY for the "NEXT AVAILABLE FLIGHT" in distress situations. What I was going for by SUGGESTING time of check in, was that perhaps the people who had been TRAVELING for the longest amount of time might make a valid argument that they need to get to some destination as early as possible. That is, say someone checked in the day before in say San Diego, on their way to Berlin via Los Angeles and London--they might be more exhausted than someone who connected in London to Berlin from say Dublin. That's why I thought maybe the airlines should try to get the people travling the longest, or who checked in the earliest on the FIRST AVAILABLE FLIGHT. Maybe that's reasonable and fair. I'm still not certain if it is, but I KNOW the airlines arbitrairly making up rules as they go along, and just giving the first available seats based on fare paid, is WRONG.
Also, Yes, I believe First Class passengers are only entitled to better food, larger seats, access to lounges and shorter/VIP check in lines. However, in distressed situations, there is NOTHING in any legal document that gives them any more rights to jump to the TOP OF THE PECKING order. That is, First Class passengers don't somehow automatically have MORE rebooking rights than anyone else.

And Yes, I understand what the term "available seats" means, in plain English, but remember, when there aren't ENOUGH "available seats" in distressed situations, there should be some KNOWN policy disclosed of EXACTLY what order or priority is given. It has to be fair. It has to be in their Contracts of Carriage. We can't trust the airlines to decide things like this on their own. Look at CORPORATE AMERICA in recent weeks: (Martha Stewart, Enron, Adelphia Cable, etc.). They can't be trusted to police themselves, so we need RULES AND LAWS AND CONTRACTS, disclosed, and applied fairly to everyone.

I stand by my statement that the "Warsaw Convention" (of the 1920's) is referenced on all airline tickets, and is in their contracts of carriage.
Jim