Can you expand? Under what conditions and by what precedent are they not enforceable (and for what purposes?). Does this apply to law enforcement interrogations? Or doctor / patient medical emergencies?
I don't think it really applies here, since the duress (the carjacking incident) came well after the legal agreement (the driver accepting Uber's TOS).
I think it's that any agreement the driver made with the carjacker would qualify as an agreement made under duress and would be unenforceable.
Duress is covered by the other reply, I think. Imbalance of powers is part of something called "Unconscionability" in the USA. There is an example in the link below too.
Basically, courts can throw contracts out when they feel they're not fair and that a side with power has taken advantage.
I guess that means if you have a heart attack, someone can bill you for cpr, but they can't bill you $100bn for cpr, even if they stand there doing nothing until you "agree".
I think this is a great question, as there are many such circumstances across a broad spectrum. If there's some legal point to pivot on (e.g. imminent physical harm) it would be good to know.
