If a scam can fool the likes of Matt Haughey, creator of MetaFilter, it can happen to anyone. He got three calls with the caller ID of his credit union and picked up on the third. After some smooth talking they convinced him to provide his ATM card’s PIN (a huge red flag) then stole $3,400 from his account.
“never give out any information about yourself in response to an unsolicited phone call.” Always call them back, and not using the number offered to you by the caller. Always.