Excuse the repitition:

it should NOT be up to the adjacent passenger to suffer and be the one to accomodate an overly larger person next to them... it should be up to the AIRLINE to ensure that all passengers are reasonably safe and reasonably comfortable... and if that means, once in a while, giving away an extra seat, that's just the cost of doing business...

And as more Americans get fatter and fatter, perhaps one day there will be enough people who have enough "weight" to put pressure on certain airlines to accomodate everyone.... or they will all boycott together, and patronize other airlines... of course no doubt, some airlines would be THRILLED if overweight people requiring two seats boycotted them...