It's decision time, and an exploration of the issues, let's use our common sense and so forth, won't cut the mustard. Me or the fattie; which is it to be? Someone has got to get off, and if it's me I'll sue.
Well it doesn't matter what you think will "cut the mustard" the situation will have been handled by the senior cabin crew member, and if called upon to make a decision, I would base that decision on their recommendation. They are the people charged with and have the day to day expertise in dealing with these matters. One thing that I would definetaly explore is the ability to create something from nothing. For example many flights are carrying off duty crewmembers (ours or somebody elses) even though they may be ordinary revenue passengers. Even where that is not an option, I may well have a spare crew jumpseat available that can be utilized to avoid a problem, provided my crew were happy with that suggestion. All sorts of options that can be explored within the day to day resources that are available to us. We want to solve a problem using common sense, compromise and resource, not create one.
However if you are not prepared to accept the seat and my decision is that we must break our contract of carriage, then sorry but off you go. It is of little concern to me whether you sue or not. That is for you and others to deal with at a later point in time. I am permitted to refuse you carriage if that becomes necessary. You have the right to seek whatever subsequent redress you see fit. The doors are closed and off we go. In other words it isn't going to become a stalemate. Next week a similar set of circumstances involving different individuals may well result in a different outcome, who knows?