In the 2013 paperback version of his "End This Depression Now!" which I'm finally reading, Krugman says:
If you've ever seen the movie "It's a Wonderful Life" which features a run on Jimmy Stewart's bank, you might be interested to know that the scene is completely anachronistic: by the time the supposed bank run takes place, that is, just after World War II, deposits were already insured, and old-fashioned bank runs were a thing of the past.
Actually the bank run happens before World War II, just as George and Mary Bailey are heading for their honeymoon. George uses his honeymoon money to save the bank.
By the end of World War II George and Mary have four children, the oldest of whom is 12 years old, which means that the Bailey Building and Loan bank run must have happened before 1933.
Also there's a picture of Herbert Hoover on the wall of the Bailey Building and Loan. His term ended March 1933.
I think Krugman's memory of the movie conflated the bank run with the other big bank-related panic in the movie - the bank examiner is coming and Uncle Billy lost $8,000.
Other than that it's a wonderful book, and the chapter "Bankers Gone Wild" is especially relevant to the play I'm working on.