I have been looking for a real-world example where the following has actually happened:

• Two or more parties signed a "circle of trust" kind of agreement, where party A performs authentication of some user, and party B relies on the authentication assertion to do something of value. Possible example: a bank outsources web authentication to a third party.
• The agreement contains a liability cause that allows party B to sue party A for damages if the authenticated user did not turn out to be the correct user. Example: somebody successfully authenticated as the account owner by party A cleaned out a bank (party B) account, but later it turned out it was not the correct owner because party A made a mistake when authenticating.
• Such an incident actually occurred, and party B did sue party A based on the "circle of trust" kind of agreement, and did get a non-trivial amount of compensation. Example: the authenticator refunded the bank, and thus the account holder, for the money that went missing.

Again, I’m not looking for an agreement of this kind, but for an actual case where somebody did get paid because they assumed liability. If you do know of one, please do let me know.