This is an option at many financial institutions and often required above a certain level of transaction, but retail customers don't hear about it quite so ofte

This is an option at many financial institutions and often required above a certain level of transaction, but retail customers don't hear about it quite so often because it's in the general category of "If you have to ask, you can't afford it." The magic word is Medallion Signature Guarantee and the mechanism is, basically, "Bank of America is satisfied that we were talking to Bob when we affixed this medallion on this paper and if we were wrong we're good for $500k." The most likely place one is likely to run into this (assuming a typical-for-HN sort of life plan) is if you accumulate a substantial amount of money in your retirement account and then try to transfer it to a different brokerage.