>...they booked a $5m loss and made a policy to never trade with that particular bank again

Maybe I am too cynical, but would many businesses retroactively agree to a deal which would cost them a ton of money? If the Process requires Is dotted, Ts crossed, and a phone call confirmation which was never placed -why eat the loss when the other party should own the error?

Citi just had a lawsuit because of paying back a loan too quickly. I expect everyone in finance to play hard ball on written agreements when it works in their favor.