Sitting at my desk at work, I get a phone call from my bank on by cell phone. "Mr. Anechoic, there appears to be a security issue with your bank account. We can resolve it for you. For security purposes, can you give your checking account number and the last four of you SSN"?
This is clearly a scam, right? I tell the guy there is no way I'm giving up that info for a random dude that calls me. He stresses again that there is an issue with my bank account, that the account will be frozen, and there is nothing he can do about it without the account and SSN information. I refuse again, and he tells me that I should go to a local bank to get it resolved. I hang up and go back to work. I log into my bank account website, and all seems fine.
After about 20 minutes, something is still bothering me, so I leave work to go to a local branch. I speak to a branch manager about what happened, and she agrees with me that it was clearly an attempted scam and the bank would never call me and ask for that information. But just to be safe, she checks my account on her computer. To our surprise, it turns out there was a security flag on my account!
She calls the bank security desk, they confirm that there was an attempt by someone in another branch a few states to get money from my account and the call I got was legit and logged in their system. We get the account locked out, and then the manager asks to talk to a security supervisor about the messed-up way they reached out to me. The security person basically said "this is how they do things" and didn't see the problem. The bank manager apologized, said it was messed up and she would try to run things up the chain to improve their process.
Damned if you do, damned if you don't.