Imagine tomorrow and everyone walks to the ATM. The question is not how long the line is. It is: where is the cash?
A deposit is a promise, not a box with your name. You hand the bank $10. They write $10 next to you. They do not drop $10 into a locker labeled YOU. Some cash stays. Most becomes a loan. If everyone wants paper today, the vault is smaller than the line. That line is a bank run — not a freeze on your account.
FDIC insures deposits to at least $250,000 per depositor, per insured bank, per ownership category. Since 1933, no depositor has lost a penny of FDIC-insured funds. In 2020 the Fed set the required reserve slice to 0%. Banks still hold cash and a Fed account. The required box was never the picture.
Homework: know what a deposit is. FDIC BankFind / EDIE if you want to look. Not a run button. Not "banks are a scam." Educational and entertainment only.
Sources
Federal Reserve Board — Reserve Requirements (0% effective March 26, 2020)
FDIC — Understanding Deposit Insurance
FDIC — Deposit Insurance FAQs
FDIC BankFind / EDIE
Investopedia — bank run; fractional-reserve banking (definitions)
Music
Background: urgent bed from Mixkit catalog ("Running Out Of Time", royalty-free).