> Up until recently, it has been considered sacrosanct that deposit holders be protected, no matter the cost.

This is simply not true. Usually bank deposits are insured by the central bank or another such agency, but there's a limit (e.g. $100k per account).

> The convention and social contract has been that you deposit money for safe-keeping in a bank.

There's indeed a social contract of sorts, but since the most of the world converted to fractional-reserve banking, banks are not pure deposit banks anymore.

In fact there have been many bank runs around the world, even in the US.

http://en.wikipedia.org/wiki/List_of_bank_runs

It's well-known that individuals who own more cash than the insured limit should spread it over several bank accounts. Of course, that is moot when the government simply confiscates your money.