I second that emotion.
What i do not believe is that the FAA, or by that any aviation authority, will do a lot about it. They are all heavily undermined by the local airlines who want nothing more than emulate how the Middle Eastern airlines abuse fdr's and by that safety.
The only defence, and by that a legal one, is to deny going into discretion too early. You can always, and by that i mean always say, that you cannot at the beginning of an operation seriously judge your state of fatigue at its end, thus discretion at the beginning of a US flight must be considered careless and will be considered as that by any judge in case of incidents. This is for a single leg. With a double leg never refuse to go! Just ask them, as a preemptive information, where the relief crew will be sent, in case you will be obliged by law to deny going into discretion due to fatigue. "Will it be Karachi or Muscat?".
Stay within the book and common sense. Any threats following a denial of discretion is a completely different matter then. That's the time aviation authorities must start action, the one of the originating just as much as the one of the arriving country.
And always remember: This is for the cause of safety in aviation and never against any company!